Final Draft

Final Draft submitted to professor

Introduction
Child acquisition of phonology is a lengthy process. Children must discover their vocal systems and learn how to use them even while the structure develops (Stilwell-Peccei, 2006) in a process of mostly well-defined but in no way discrete stages (Stark, 1980). The typical child achieves a number of milestones along a general timeline, though with plenty of extant individual variation (Lust, 2006).

It is easier to track a child’s language development based on the length and construction of an utterance. The acquisition of a particular sound is difficult to monitor because its production can be affected by all number of factors such as word length or the environment in which a given sound occurs (Ingram, Christensen, Veach, Webster, 1980), and its appearance before or after any other sound can be influenced by articulatory complexity, its rate of occurrence within the target language, and functional load (Van Severen, Gillis, Molemans, Van Den Berg, De Maeyer, & Gillis, 2013, Hoff, 2013). Some generalizations as to the development of phonological acquisition can be made, however, such as the order of pre-linguistic stages, which sounds appear, and which sounds do not.

Stages of Pre-linguistic Development
Researchers in the field of child language development agree the period before an infant can speak has a number of development stages. As to how those stages are defined and when they take place, however, they tend to disagree. The onset of a stage is not always particularly clear, like that of vocal play, and behaviours making their debut in one period appear just as frequently in its successor (Stark, 1980).

Vegetative, Reflexive Sounds
The first stage of phonological production development, vegetative and reflexive sounds, starts at birth and is characterized by how a neonate’s immature vocal tract and brain (Lust, 2006) limits their ability to produce phonation. For about a month and a half, an infant can only produce reflexive and vegetative sounds like a vocalic cry when in discomfort or vocalizations that give the impression of proto-consonants when air catches on parts of the vocal system when breathing, burping, or other basic, living sounds (Stark, 1980, Hoff, 2013).

Infants can distinguish their mother tongue from a foreign language from birth, and can discriminate between two foreign languages as well as between words and non-words, and prefer their mother’s voice to all others (Mehler, Jusczyk, Lambertz, Halsted, Bertoncini, & AmielTison, 1988).

Analysis
Language perception in infants can be tested by gauging interest with regards to their rate of sucking, in this case, language discrimination. Neonates can do this from birth, however the neurons responsible begin to be cannibalized almost immediately and prosodically-similar languages, which English, Cantonese, and the East Slavic language family are not soon become indistinguishable (Mehler et al., 1988).

Infants prefer the sound of a human voice over all other sounds and will attend the source. (2, 4, 8, 12, 15, 17, 19, 22, 25, 42); Mehler et al., 1988).

Cooing and Laughter
Infants begin to vocalize contentment as early as 6 weeks (Stark, 1980), and they do so usually with a “coo” (Hoff, 2013). This is a more musical vocalization (Gillen, 2003), initially with only one, long vowel-like sound; in fact, the only recognizable speech sounds at this point are vowellike.

As the infant’s vocal system develops and she begins to learn how it works, she begins to produce her first consonantal sounds, typically at the back of her mouth and reminiscent of [k] and [g] (Hoff, 2013), and combines them with vocalic sounds into a consonant-vowel-like early syllable (Lust, 2006).

Vocal Play
The discovery that sounds can be combined leads way to the “vocal play” stage, also known as the “expansion stage” (Stark, 1980). Infants mix together a variety of sounds and do not limit themselves to “isolated” consonantal and vocalic vocalizations (Goodluck, 2001) but play with friction noises (Hoff, 2013), nasal murmurs, and behaviours such as squeaking or yelling (Stark, 1980). Although the infant produces vocalizations with consonant and vowel-like features, syllables of this ilk remain as of yet undeveloped in terms of their temporal characteristics and production values, such as syllable-timing fundamental frequency, or prosody (Lust, 2006).

Infants develop more of a sense of their proper timing and articulation, however (MacNeilage, 1980), as they produce longer and more complicated series of sounds (Hoff, 2013) and eventually progress into “marginal babbling” (Stark, 1980).

Reduplicated Babbling
The playful sounds from the expansion stage continue throughout the reduplicated babbling stage, the onset of which typically occurs when the infant is about 6 months old (Stark, 1980). The hallmark of this stage is a long string of nigh-uniform consonant-vowel syllables whose timing bears a much greater resemblance to adult speech than the infant’s productions thus far (Stark, 1980). Their use of velar stops has decreased considerably—they may disappear from their production repertoire completely for some time—and she produces consonant-like sounds at the front of her mouth, such as [m, n, p], or [d] (Hoff, 2013).

Their vocalizations show the first signs of language-specific characteristics, though at the beginning, the effect is only obvious to phoneticians as only vowels and suprasegmental factors are affected, but by the time an infant is 8 months old, an adult may be able to distinguish two typical infants babbling in different target languages (Goodluck, 2001), however experimenters will usually have them to listen to a recording as infants rarely contribute babbles to a conversation; in fact they prefer to babble when they are alone.

By the end of this stage of simpler babbles, caregivers’ expectations as to what they consider a contribution to a conversation on the infant’s part are higher than they have ever been, encouraging their infant to offer CV-like utterances as opposed to vocal play behaviours (Clark, 2009).

Analysis
In dialogue two, at seven months, Fei Yen’s vocalizations are steadily shifting to front consonants:

dadædadadədægæ dædə].”
 * 13. “[dadægægagəgædæ gagəgədədæ].”
 * 12 syllables; [d]: 5, [g]: 7
 * 16. Fei Yen waves Lady Quack about. “[dædə gəgədədæ gædədə gagəgə].”
 * 12 syllables; [d]: 6, [g]: 6
 * 21. Fei Yen bats at Lady Quack. “[gagædæ dəgədə dadægædadə dægæ].”
 * 13 syllables; [d]: 8, [g]: 5
 * 23. Fei Yen rattles Lady Quack. “[dadæ dadægægagəgædæ dədægædadə dægæ].”
 * 16 syllables; [d]: 10, [g]: 6
 * 25. Fei Yen plunges Lady Quack once more into the water. “[dagada gagægədədæ
 * 17 syllables; [d]: 10, [g]: 7
 * 27. Fei Yen waves Lady Quack. “[dadæ dæda dægæda dəgagædæ dadaga gædæ—]”
 * 16 syllables; [d]: 11, [g]: 5
 * 32. Fei Yen reaches for Lady Quack. “[dadæ dæda dægæda dəgagædæ dadaga gædæ].”
 * 16 syllables; [d]: 11, [g]: 5

Locke (1983) writes of an “increase in dominance” of [d] over [g] in “noncrying vocalizations”, noting that by the time an infant is 7 months old, [d] occurs 54% of the time an infant would use either [d] or [g]. Predominant vowel-like sounds during this time include [a, æ], and [ə].

Stark (1980) describes how the likelihood of an infant babbling is greater than in “any other context” when the infant has an object she can manipulate, especially one which can be waved or shaken or when she is “visually exploring the environment”, like Fei Yen’s interactions with Lady Quack in the excerpt above, but rarely in a conversation, as seen in dialogue two, 7 months, lines [16-21]:


 * 16. “Time for soap.”
 * 17. Fei Yen trills, grabbing for his fingers.
 * 18. “Nope, soap.”
 * 19. Fei Yen huffs, bats at Lady Quack.
 * 20. “I know, I know.” Mr Xiong squeezes shampoo onto his hand.
 * 21. Fei Yen bats at Lady Quack. “[gagædæ dəgədə dadægædadə dægæ].”

Fei Yen does not offer babbles in her dialogue with her father; she prefers to speak to him with vocal play behaviours and only babbles when he is not offering conversation.

Nonreduplicated Babbling
The onset of variegated babbling is not as clearly delineated as other stages (Stark, 1980), however one may safely assume a typical, 9-10 month old infant has reached this stage and will likely prolong the overlap with pre-linguistic schemas and early word use for another couple years (Clark, 2009). Unlike reduplicated babbling, an infant will offer variegated babbles as conversation (Stark, 1980). While true consonants become more well-defined, language-specific characteristics become less obvious and more difficult for adults to discriminate (Hoff, 2013). Infants typically begin to use a greater variety of consonants, vowels, syllables, and prosodies (Stark, 1980), and begin to sound as if they are speaking the target language even though they still only produce nonsense sounds (Hoff, 2013). Infants who remain at this stage and produce quite a bit of this "jargon" are known as "intonation babies", while infants who quickly proceed to learning the labels of their environment are "word babies". An infant will make their preference clear around their first birthday (Goodluck, 2001).

Analysis
In dialogue three, 11 months, Fei Yen exhibits the overlap of variegated babbling, pre-linguistic schemas, and early word use:


 * 127. “[mmm]!” Fei Yen reaches again.
 * Pre-linguistic schema for a request (see “Pre-linguistic Schemas”)
 * 128. “Feiby, what’s wrong?”
 * 129. “[gʌb]!” Fei Yen stomps her feet.


 * A short varigated babble

As is typical of an infant at this stage, Fei Yen’s babbling has a greater variety of syllable types and sounds:


 * 99. “[dæ].” Fei Yen streeetches, pats his crown.
 * 101. “[dædədæ-dədædædəb].”
 * 103. “[dəb-dəp. dædəb].” Fei Yen tilts Hu’s head this way--“[dəddæbgə].”-- and that. “[gæb. gəgɒbdəbgəb].”
 * 105. “[ta. dædəbdəbgɒb].” Fei Yen rubs Hu’s crown with the heel of her hand.
 * 107. Fei Yen yanks Jin’s ear. “[tɒb].”
 * 109. “[tɒp]?” Fei Yen huffs, presses her mouth to Hu’s crown.
 * 112. “[təbtɒp. tɒbtəpdɒp].” Fei Yen pats around with more force, brow furrowed. “[təpdæpgəp].”
 * 114. “[gɒpkə].” Fei Yen mouths Hu’s head, taps with her front teeth. “[ʌb].”
 * 116. Fei Yen pulls away. “[gɒbdəbtɒbtɒpdəpgʌb].” Frowns, digs in her teeth.
 * 123. “[tʌp]!”
 * 125. Fei Yen goes pink, face scrunching. [gəp]!”
 * 129. “[gʌb]!” Fei Yen stomps her feet.
 * 131. Fei Yen sits down heavily. “[kʌb].” Bursts into tears.

Instead of strings of CV syllables with very little variation, Fei Yen babbles with both CV syllables and CVC syllables with more than one difference between each segment and with a greater variety of articulation and voicing, such as word initial [t, g, k], and [d], and word final [p] and [b], than in the previous, reduplicated babbling stage where she only produced word initial [d] and [g].

Since Fei Yen’s babbling is also serving to as a means of communication (Stark, 1980), she attempts to limit her production of different sounds to those in the neighbourhood (Hoff, 2013) of her target word, [kʌp].

Pre-linguistic Schemas
Children produce meaningful utterances around 10 months; meaningful /words appear around 12 months. The former are not ‘words’ by virtue of not sounding adult-like, and have usually developed from an isolated segment of variegated babbling. These utterances constitute “protowords” but fail to capture an important distinction of early word development; at this stage, a meaningful utterance is a combination gesture-vocalization as much a part of their lexicon as words and will continue to do so until the child is two years old (Clark, 2009).

These utterances typically have properties that make them easier to pronounce, for instance, they tend to be one or two syllables and they are usually open. [m, p, d] are found consistently in children’s early vocabularies, while [θ, ð, l, r] and consonant clusters are consistently absent, however there is considerable variation in production repertoires (Hoff, 2013).

Analysis
In dialogue three (eleven months), Fei Yen communicates in a fashion characteristic of the “prelinguistic schema” (Clark, 2009) stage of development. She uses consistent vocalizations and gestures in highly constrained ways (the 'constrained’ aspect is not as obvious):


 * “[h]!” + waving ([5]): “Hello!”
 * The voiced glottal glide [h] is one of the consonants which appears quite frequently in infants’ repertoires as they near the onset of their first words. The liquid [l], however, is not, and Fei Yen deletes it as well as the vowels. She made this gesture watching people try to get someone’s attention from a distance as she cannot yet bow.


 * “[ɛ]?” she asks, patting, at hip level, the air beside her ([8]): “May I stay, please?”
 * Fei Yen cannot yet manage the stop cluster [st] so she deletes it, leaving [ɛ] (McLeod, Van Doorn, & Reed, 2001). She learned this gesture from people asking variations of, “would you like to sit (here)” and patting the seat beside them.


 * Fei Yen beams, “[dæŋ]!”, and kisses the air in [x]’s direction ([12, 53, 63]): “Thank you!”
 * Fei Yen reduces two syllables to only the one, simplifies [θ] to [t] and voices it to [d], and reduces the [ŋk] cluster to [n]. She created this one by watching her parents at the breakfast/supper table; one would get something for the other who would thank them and kiss their cheek.


 * “[ækə]” ([16]): Proto-version of “All clear!” which, to Fei Yen, means everything from “Let’s go!” to “as you were”, “that’s okay”, and “we’re good”, among other uses.
 * This is an example of a segmentation error, as Fei Yen perceives this two word phrase as one word, "allclear". She reduces it to a VC-V syllable, one of the new consonant-vowel combinations found in infant's variegated babbling (Stark, 1980).

The liquid [l] is not yet present in her repertoire; as her articulatory and cognitive prowess develops, she will coalesce the [ɒl] of "all" into [ɔ], but for now, such a sound is too complicated in this more complex environment for her brain to manage. The liquid [r] will not appear for some time and by deleting it she both removes an unpronounceable sound from the utterance and creates an easier, open syllable from a more difficult, closed syllable.


 * “[bæ]!” waves Fei Yen ([20]): “Goodbye!”
 * The stop, [b], is a voiced front sound, two features which make it a very straightforward sound to produce, unlike the diphthong [aɪ̯] so Fei Yen has coalesced the two vowels into [æ].


 * Fei Yen snores, giggles, and grins ([55]): How Fei Yen says “I slept well” which she picked up from roleplaying games and books as both denote sleeping deeply with snores. She finds the sound of snoring funny.
 * She does not yet know the word “snore” but she does know the sound.


 * “[mmm].” ([51, 116, 122]): making a request
 * An attempt to communicate “to me!”, possibly failing due to the cognitive load of attaching meaning to an utterance (Werker, Fennell, Corcoran, & Stager, 2002).


 * Fei Yen makes a sing-song-y sound ([67]): “You’re welcome”
 * This is the intonation contour of “you’re welcome”


 * Fei Yen replies with a high, nasaly sound and a happy face ([69]): "I like you!”, happy sounds
 * She does not yet have words to describe affectionate and happy feelings so she just uses a collection of sounds in a major key.


 * Fei Yen hums a sigh ([73]): sad sounds
 * An attempt at an adult’s sympathetic sigh (though she only understands the basic, ‘sad’ element) around a sippy cup.

Fei Yen will continue refining these schemas well after she has begun speaking, like her dietic gesture in dialogue four, when she is thirteen months old:


 * 2. "Which one shall we learn today?" asks Hermann.
 * 3. Fei Yen points to a symbol on the chalkboard. "Da."

The importance of these gestures will continue up until the time around Fei Yen’s second birthday (Clark, 2009), so in dialogue six, (22 months), Fei Yen continues to make use of them:


 * 29. “What’s up, Feiby?”
 * 30. “Duck!” Fei Yen waves Mister Soap at Ducky.

She also displays two transitioning representational-symbolic gestures (Morgan, 2014) in [55] and [59]:


 * 54. “That is some /incredible learn-age there, kid.” Miyahira holds out her fist. “Awesome fistbump of smartness.”
 * 55. "Yosh!" Fei Yen gleefully throws forth her own.

And,


 * 58. “That’s my cue,” apologizes Miyahira. “Gotta jet.”
 * 59. “Byebye,” waves Fei Yen.

Babbling and First Words
Some infants go through a silent period around the same they begin to walk, which led some researchers to believe that babbling and early word production were two entirely different, unrelated systems. This may be an issue of cognitive load, however, suggested by Werker et al. (2002) with regards to word learning. Research has also found that an infant's preferences when babbling "predict quite accurately" their first words and probable deformations (Stark, 1980). At this point, only 11 consonants account for almost all the consonant sounds babbled by American English-learning 12 month olds: [h, w, j, p, b, m, t, d, n, k, g] (Hoff, 2013).

First Words
A child’s first meaningful words are typically spoken any time between 9 and 14 months (Lust, 2006) and label common, concrete concepts with which they interact frequently (Clark, 2009). These words follow many of the same phonological processes as vocalizations found in a child’s pre-linguistic schemes. They tend to be one open syllable, a reduplicated utterance, or two different syllables (Hoff, 2013).

Analysis
As is expected in the variegated babbling stage, Fei Yen no longer uses babbles as exercise but as dialogue, and replies with jargon:


 * 98. Jin asks, “What’s got you so interested?”
 * 99. “[dæ].” Fei Yen streeetches, pats his crown.

Hoff (2013) writes, “A child who is very interested in social interaction … might be more driven to use whatever means is available for interaction.”, so upon meeting failure, Fei Yen adds to her original reply with variegated babbles in the continued hope of communicating her meaning. She offers as many sound combinations as close to the target word, [kʌp], as she is able while honing in on the proper articulation and voicing:


 * 122. “What’s up?”
 * 123. “[tʌp]!”

and the proper final consonant.
 * Proper voicing, proper obstruction, but wrong place of articulation; proper vowel
 * 124. “Why’re you biting him?”
 * 125. Fei Yen goes pink, face scrunching. [gəp]!”

too far to the front; proper final consonant.
 * Proper place of articulation but voiced; proper degree of closure for the vowel but
 * 126. “Feiby?”
 * 127. “[mmm]!” Fei Yen reaches again.


 * Attempting a different tactic by using a schema she knows they understand
 * 128. “Feiby, what’s wrong?”
 * 129. “[gʌb]!” Fei Yen stomps her feet.


 * Proper place of articulation but incorrect voiced, target vowel, target final consonant
 * 130. “Fei Yen?”
 * 131. Fei Yen sits down heavily. “[kʌb]!” Bursts into tears.

voicing
 * Correct initial consonant; correct vowel, proper place of articulation but incorrect

Stops like [k] and [p] are both early-developing sounds, and [p] is a sound that consistently appears in children’s early words (Hoff, 2013).

Single Words
Consonant clusters, fricatives, and liquids are not produced, while sounds articulated closer to the front of the mouth, like [m, p], and [d] are produced extremely frequently, comprising almost all the consonantal production of a toddler’s utterances along with eight other consonants (Hoff, 2013).

The single word period is not a true stage like babbling or cooing, but a number of processes that every word goes through (Clark, 2009). A typical child will learn that specific sound combinations refer to specific objects. In the first half of the process, a toddler separates a segment from the speech stream, assigns it to any number of meanings, and approximates a production. This utterance tends to be of one, open syllable; one of the biggest differences between the toddler’s production and the target. Words undergoing the second half of the process more closely resemble the latter in the number of sounds, however they may not be produced in an adult-like manner (Clark, 2009).

Early Single Words
In the early single word period, a child’s production vocabulary consists of very few words, none, if any, resemble the adult forms (Hoff, 2013). They tend to be holophrastic utterances as a child will use a nonword if their utterance really is only one word long (Clark, 2009).

Analysis
Fei Yen is three months past her first words, and the quality of her productions are hindered by her still-developing brain (Goodluck, 2001), so she is only capable of speaking one word at a time and without any prosodic notions, like contrastive stress:


 * 7. Fei Yen frowns. "Na-ma."

If Fei Yen could speak in an adult like manner, she would have said, “I didn’t say ‘llama’, I said /lambda.” Early pronouns, like “I”, negations, and contractions will not appear until after she can speak in two-word utterances (Brown, 1973) and she will not have enough articulatory control to produce contrastive stress until she is almost three (Stilwell-Peccei, 2006).

As is typical of children in the early single word period, Fei Yen cannot produce the fricative [ð] and substitutes [d] in its place:


 * 3. Fei Yen points. “Da one.”

The lateral liquid [l] also causes her difficulty, so she replaces it as well, this time with the nasal [n], and deletes final consonant, [d]:

13. Fei Yen giggles. "Nama."

Children tend to reduplicate the first syllable (partial, in the case of [7, 9, 13]) and delete the final consonant ([d] in [3, 7, 9, 13]).

Both [d] and [n] are early acquired sounds, the former of which consistently appears across children’s early production vocabulary (Hoff, 2013). As for why children’s phonological processes replace targets with sounds they cannot produce in other environments, in this case, the fricative [s] another fricative, [ʃ], no one really knows (Lust, 2006):


 * 11. Fei Yen makes a show of thinking about it, then nods. "Yesh."

Also illustrated, in [9], is children's ability to recognize their own deformations; that is, they are saying the target word perfectly but they cannot produce it and they know it (Lust, 2006):


 * 6. "This is lambda."
 * 7. "Naaama."
 * 8. He stifles a laugh. "Llama?"
 * 9. Fei Yen frowns. "Na-ma."

Later Single Words
A child’s vocabulary at fourteen months shows some growth since the earlier single word stage.

At this point, a child can begin implementing the later part of the single word period around 14 months of age, producing their first few adult-like words, even if their production capabilities are limited (Clark, 2009).

A child appears to use the contents of their meager vocabulary in either highly constrained ways or in a fashion which suggests overgeneralizations. However, since they have yet to fully understand what parts of their environment belong with what, it may be that children do neither and simply they attach the label to a specific characteristic (Stilwell-Peccei, 2006).

Analysis
In dialogue four, (15 months) Fei Yen exhibits a number of trends typical of a child’s language development, such as making use of phonological processes, having difficulty with the speech stream, and compensating for a limited vocabulary.

Fei Yen implements a number of phonological processes such that she can approximate sounds in words she would otherwise not be able to produce. Some of them include creating open syllables by deleting word final consonants, especially late-developing sounds like liquids, simplifying fricatives, and strategies for consonant clusters.

Fei Yen’s use of her vocabulary is characteristic of a child who wants to communicate but cannot do so in an adult-like manner. She thus relies on holophrastic utterances and overgeneralizations, but some of her word choices reflect segmentation errors of the speech stream and of her world (thus having difficulty mapping words and sounds to their proper meaning), however, and not conscious choices to compensate.


 * “[tsɑ]!” ([1, 9, 28, 36]): “Stop!”; an exclamation to denote something is happening
 * Fei Yen has coalesced the fricative-stop cluster into one consonant, the affricate [ts] (McLeod et al., 2001) and created an open syllable by deleting the word final stop, [p]. Even without Fei Yen’s meddling, “Stop!”, in a construction sense, is a holophrastic utterance, meaning “stop what you’re doing!” and “watch out!”. She has overgeneralized its use, however, to mean “watch out” in a number of different contexts, like when driving an imaginary vehicle.
 * “[ɔkɪə]!” ([3, 11, 25, 34]): “All clear”`; the cue for things to start
 * Fei Yen still prefers open syllables, and since she cannot produce liquids, deleting the word final [r], she satisfies both needs with one process. She coalesces the vowel [ɒ] and the word final liquid [l] into [ɔ] for the same, liquid-avoiding reason. This two word utterance remains the victim of a speech segmentation error; as seen in dialogue three, she hears the two words as only one. This is a case where an overgeneralization may not really be an overgeneralization (Stilwell-Peccei, 2006) as she uses it as a label for starting and restarting, depending on context.
 * “Boooooo” (with a deep timbre; [5]): “Vooooo”; the sound of a very large thing moving.
 * The fricative [v] remains unpronounceable, leading Fei Yen to simplify it into the stop [b] (Ingram et al., 1980).
 * “Beee! Beee!” ([7]): the sound of doing something new (a ‘reverse’ alarm; a vehicle reversing).
 * “[fu].” ([13]): “Phew”
 * Fei Yen simplifies the [fju] fricative-diphthong combination to a more straightforward fricative-vowel combination (Ingram et al., 1980).
 * “Boomboom” ([5]): “Vroomvroom”; to head off, to ride (in a cart), to go somewhere.
 * Fei Yen cannot produce the fricative-liquid cluster [vr] so she deletes the liquid and simplifies the fricative into a stop (McLeod et al., 2001, Ingram et al., 1980). This is also her label for anything on which she can ride; the maintenance workers who ferry Fei Yen and her caregiver over especially long distances, without fail, announce the beginning of the drive with “Vroom vroom!”
 * “Maaau” ([32, 39]): a whiny sound (the sound of a brake engaging)
 * Another of Fei Yen’s compensating overgeneralizations; she approximates the sound of a brake engaging by imitating a cat as sounds are more readily identifiable in the latter than in the former.
 * “[dæŋju]” ([41]): “thank you”
 * Fei Yen has incorrectly parsed the speech stream in such a way that she hears “thank” and “you” as one segment. She has stored it as an unanalyzed whole which is part of why she pronounces it here and simplifies the [ju] in “phew” (the other reason being children’s production of a sound varies from one utterance to the next (Clark, 2009)). Fei Yen also simplifies [θ] to [t] and voices it to [d], and reduces the [ŋk] cluster to [ŋ].

As Fei Yen’s fifty first words near the end of their single word period, she consistently produces them in an adult-like manner; however the propositions implied in her holophrastic utterances remain as cryptic as ever, as seen in dialogue six, 22 months:


 * 9. Fei Yen narrows her eyes. “Duck.”
 * “I am [Mister Soap]; gummies, prepare to be smooshed.”
 * 15. “Duck—” Fei Yen looks at Mister Soap.
 * “I am [Mister Soap]—”
 * 20. Fei Yen says, “Duck.”
 * “[Mister Soap] is like Ducky.”
 * 22. “/Duck.”
 * “[Mister Soap] and Ducky are both called ‘duck’.”
 * 24. “/Duck!”
 * “They’re both called ‘duck’!”
 * 26. “Duck!” Fei Yen grabs Mister Soap. “Duck!”
 * “Mister Soap is called ‘duck’!” and “Ducky is called ‘duck’!”
 * 28. Fei Yen fumes, twists in Charlie’s lap. “Duck.”
 * “Why doesn’t he understand they’re both ducks.”
 * 30. “Duck!” Fei Yen waves Mister Soap at Ducky.
 * “They’re both ducks!”
 * 31. “[wɒkə mʌdnɒ ɔkɪr]!”
 * “Getting help is a great idea!”
 * 39. Fei Yen grumbles, throws down Mister Soap. “Duck.”
 * “I can’t believe I have to wait to tell them they’re both ducks.”
 * 45. Fei Yen, picking up Mister Soap. “Duck.” Points him at Ducky. “Duck.”
 * “Mister Soap’s a duck.” And “Ducky’s a duck.”
 * 48. Fei Yen bounces. “Duck! Duck-duck!”
 * “They’re both ducks! Mister Soap, a duck, Ducky, and duck!”

Her use of nonwords for single word productions has decreased considerably (Clark, 2009), using adult-like words instead, like “Boom!” ([11]).

Transitional Words
Once children speak their first words, their language acquisition seems to grind to a halt, spending months using only one-word, occasionally holophrastic (Clark, 2009), utterances for no physiological, cognitive, or vocabulary reason (Lust, 2006). This single word period eventually develops into transitional words, such as vertical constructions or word-jargon combinations (Hoff, 2013). Vertical constructions are multiple, related utterances in which each word is separated by a pause, and word-jargon combinations include one recognizable word in a string of babbling.

Analysis
Fei Yen’s progression into longer utterances is heralded by the appearance of vertical constructions she has been scattering throughout her speech, such as:


 * 48. “Tarding. Cannon.”

The utterance, in adult, would be “Charging cannon”, but for whatever reason (Lust, 2006), Fei Yen cannot yet manage a proper two-word utterance. “Tarding” is also an example of an unanalyzed whole, a form of speech segmentation error where an utterance with multiple morphemes is perceived and produced as one large chunk, that is, Fei Yen has yet to learn that “charging” is “charge+ing” and will not recognize the individual morphemes on their own (cite).

Fei Yen simplifies the fricative [tʃ] and the affricate [dʒ] into the stops [t] and [d], respectively, while [kænən] has emerged from the single word period as an adult-like production. She can also now produce the liquid [r] in word-final positions:


 * 49. “[wɒkə mʌdnɒ ɔkɪr]!”

In this word-jargon combination, Fei Yen shows she still has yet to master the liquid [l], either in a word final position or in a consonant cluster, like this stop-liquid, [kl], cluster wherein she deletes it (McLeod et al., 2001), not unlike her phonological process for the liquid [r] when it occurs in a word-final position and closing a syllable.

Two-Word Utterances
The child has a good grasp on most of the sounds in of their language, thus their early implementations of syntax and morphology are almost fully intelligible, and upon grasping the productivity of language, a child can express a number of variations within the handful of relational meanings to which their utterances are constrained.

Analysis
Around line 15, Fei Yen has the epiphany that everything has a label (Ingram, 1989) and the arbitrary nature of those labels (Gillen, 2003), shortly moving on to two (and later, three) word utterances (though probably not this quickly) by line 66:


 * 66. “Duck grow.”

These two words have both completed the single word period successfully and are produced in an adult-like manner, giving them the opportunity to express an agent-action relationship, one of the eight relational meanings Brown (1973) identified in children’s two-word utterances.

Conclusion
Children will not fully acquire the phonological inventory of their language for years, though how old they are varies from child to child. This lengthy process proceeds with no discernable rhyme or reason; whatever logic dictates their learning remains hidden by the very phenomenon scientists wish to study.