Chapter 9 Cros s-Linguistic Trends in the Acquisition of Speech Sounds

Chapter 9Cross-Linguistic Trends in the Acquisition of Speech Sounds KrisztinaZajdó

Introduction • Starting at the end of the 19th century, parental diary studies documented speech acquisition in monolingual English children • Roman Jakobson (1896-1982)was a pioneer in the study of child speech development from a structuralist perspective • This chapter • Retraces the history of cross-linguistic research regarding the acquisition of phonologic systems and • Shows how speech sound development follows certain universal trends across many different languages • Separately for vowels and consonants • Predicted acquisition patterns • Evidence from selected research studies • Evidence from meta-analysis of studies of selected languages

The Laws of Irreversible Solidarity • Structural linguistics (Roman Jakobson, 1941/1968) examined languages in terms of inherent structures • Levels • Sentences, phrases, words, syllables, sounds • Within sounds: classes defined by front vs. back of mouth, high vs. low vowel, continuant vs. non-continuant • Languages have some language-specific patterns in their phonologies • English and German allow complex C clusters in initial and final positions but Japanese and Cantonese only have C singletons in onsets and nasals in final position • In German, /ç/ follows high and mid front vowels and /x/ follows all other vowels (complementary distribution) • Languages (as spoken by adults) share some common trends in their phonologies • If a language has fricatives, it also has stops • If a language has front vowels, it also has back vowels • Jakobson was interested in how children’s speech acquisitions mirror these cross-linguistic trends

Irreversible Solidarity • If a language has A, this implies that it also has B (also referred to as implicational hierarchy) • A -> B • Front vowels -> back vowels • Fricatives -> stops • Back consonants -> front consonants • A = less common, less basic = “marked” • B = common, basic = “unmarked”

Jakobson’s Prediction Prediction: Children follow the laws of irreversible solidarity when acquiring the speech sounds of their language Another way of stating the prediction: Children acquire the unmarked sounds in their language before the marked ones

Theoretical Framework • Children need to produce maximally different speech sounds to differentiate between different words • Children follow a universal order of steps of creating binary oppositions (each opposition is between an unmarked and marked set of sounds): • Low vowels, e,g. /a/ vs. completely closed consonants , e.g., /b/ • Nasal sounds vs. oral sounds • Labial sounds vs. non-labial sounds • Low vowels vs. high vowels • Front vowels vs. back vowels, high vs. mid vowels • Children follow a universal order of steps of creating binary oppositions • Children sometimes make errors by producing the wrong member within a target class, e.g., [d]/b (both front C)

Cross-Linguistic Studies of Speech Sound Acquisition Jakobson’s observations in the 1930s were based on data from more than a dozen languages Since then, great progress has been made in describing children’s acquisition of English but fewer studies have addressed other languages Languages differ in terms of structural properties Children differ in their approach to acquiring their phonologies Hypothesis: Children may follow both cross-linguistic and language-specific trends

Limitations of Research on the Acquisition of Speech Sounds Cross-Linguistically • Caveat: cross-linguistic studies have different properties, which limits our ability to make direct comparisons • Study design • Sample size • Participant selection criteria • Speech elicitation strategy (imitation, picture naming, spontaneous speech) • Recording technique • Definition of concepts • Despite many limitations in the research studies, Jakobson’s predictions found full or at least partial support

Universal Steps in Vowel Acquisition Proposed by Jakobson • Regarding vowels, Jakobson predicted that • Children learn to differentiate vowels and consonants early in development (Step 1 of speech acquisition) • Children learn to contrast low and high vowels at a certain stage during speech development (Step 4) • The final stage of speech sound development (Step 5) is learning to contrast front and back or high and mid vowels

Universal Trends inVowelAcquisition Proposed by Jakobson: Step 1 • Step 1 Prediction: Children learn to differentiate vowels/consonants early in development • Evidence from babble: • CV, VC, or CVCV sequences in canonical babble in English; CV most common cross-linguistically • Evidence from speech productions (Tables 9.1 and 9.2) • Children do acquire vowels earlier than consonants in general • However, certain vowels take much longer than previously thought to be produced with adult-like accuracy • The size of a language’s vowel inventory does not seem to influence the acquisition of vowel accuracy

Universal Trends inVowelAcquisition Proposed by Jakobson: Step 4 • Step 4: Children learn to contrast low/high vowels • Evidence from cross-linguistic data: • In canonical babble, mid and low front and central vowels are most frequently produced across languages; very few high vowels are produced • High vowels are acquired after the babble stages

Universal Trends inVowelAcquisition Proposed by Jakobson: Step 5 • Step 5: Children learn to contrast front vowels/back vowels, high/mid vowels • Evidence from cross-linguistic data: • In canonical babble, very few back vowels are produced; they are acquired later during the first words stage • The contrast between high and mid vowels is not acquired until the first words stage

Cross-Linguistic Vowel Acquisition Data: Making Observations from Several Languages • Seven languages of different origins and with different vowel inventory sizes were compared for percent vowels correct (Table 9.1) • Indo-European • Greek (5 vowels) • American English (18 or 19 monophthongs plus 3 or 4 diphthongs) • Uralic • Finnish (8 monophthongs and 18 diphthongs) • Hungarian (14) • Sino-Tibetan • Puthongua (9 monophthongs, 9 diphthongs and 4 triphthongs) • Cantonese (8 monophtongs with 3 allophones and 11 diphthongs) • Bantu • Sesotho (9)

Table 9.1 Percent Vowels Correct in Seven Languages *The number of monophthongs increases to 19 if we count the /ɔ/ vowel. The number of diphthongs increases to four if we count /ju/ as a diphthong (Smit, 2007). Note: There were no differences in boys vs. girls In some cases, mastery of all vowels was achieved surprisingly late Focus Questions At what age do children reach 90% accuracy for vowels? What is the size of the vowel inventory of the two earliest-acquired vowel systems? The two latest acquired ones?

Working definitions of “correct production” vary among the studies • The claim that vowels are acquired early (earlier than consonants) appears to be only partially supported by cross-linguistic data • Compared to age of acquisition of consonants (Tables 9.2 and 9.3), vowels tend to be acquired earlier • The size of the vowel inventory does not seem to correlate with age of mastery • Some vowel errors were observed in children up to age 8 years • While vowels are produced relatively accurately early in development, it may take years for typically developing children to reach adult-like accuracy levels

Universal Steps in Consonant Acquisition Proposed by Jakobson • Regarding consonants, Jakobson predicted that • Children learn to produce maximally closed consonants (e.g., bilabial stops) as part of the earliest step in speech sound acquisition (Step 1) • Children acquire the contrast between nasals and oral stop contrasts (Step 2) • Children acquire the contrast between labials and non-labials (dentals; Step 3).

Universal Trends in Consonant Acquisition Signaled by Cross-Linguistic Studies • Seven languages of different origins and with different consonant inventory sizes were compared for percent consonants correct (Table 9.2) • Uralic • Hungarian (27 plus 7 allophones) • Sino-Tibetan • Puthongua (22) • Cantonese (19) • Bantu • Sesotho (9) • Altaic (Turkic branch) • Turkish (20) • Indoeuropean (Germanic branch) • German (24) • Semitic • Jordanian Arabic (28 plus 6 allophones)

Table 9.2 Percent Consonants Correct in seven languages Note In Hungarian and Turkish, errors were still observed in 8-y-o children Focus questions: At what ages do children reach the 90% accuracy mark? How does the age of consonant mastery compare to the age of vowel mastery? What is the consonant inventory of the two earliest-acquired consonant systems? The two latest-acquired consonant systems? * The number increases to 65 (2) if we count labialized consonants as contrastive phonemes ** M = Male, F = Female, A = All

Ten languages with different origins and consonant inventory sizes were compared for age of mastery of individual phonemes (Table 9.3, not shown) • Semitic • Jordanian Arabic • Maltese • Sino-Tibetan • Puthongua • Cantonese • Indoeuropean • German • Greek • Uralic • Hungarian • Japonic • Japanese • Language isolate or related to Altaic • Korean • Tai-Kadai • Thai

Universal Trends in Consonant Acquisition Proposed by Jakobson: Step 1 • Step 1: Children acquire the maximally closed consonants first (e.g., /b/) • Evidence from cross-linguistic comparison: • In many but not all languages, bilabial stops are among the first to be acquired • Where there is a voiced/voiceless cognate pair, /p/ is acquired before /b/

Universal Trends in Consonant Acquisition Proposed by Jakobson: Step 2 • Step 2: Children acquire the contrast between nasal and oral consonants • Nasals vs. bilabial stops: Evidence from cross-linguistic comparison • In several languages (e.g., German, Jordanian Arabic), nasals are acquired before the bilabial stops • However, in other languages (e.g., Cantonese, Hungarian), nasals are not produced accurately until later • No clear pattern was seen in the data examined for this chapter

Universal Trends in Consonant Acquisition Proposed by Jakobson: Step 3 • Step 3: Front consonants are acquired before non-front consonants • Evidence from cross-linguistic comparison • This is generally true • Exceptions were noted in some languages regarding glottal fricatives (/h/) • /h/ may have a special status among back consonants – cf. /h/ replacements in severe speech sound disorder

Cross-Linguistic Consonant Acquisition Data: General Observations from Several Languages • In general, vowels are mastered earlier than consonants • There is no clear correlation between consonant inventory size and age of consonant mastery (resembling the findings for vowels) • In Hungarian and Turkish, consonant errors are still observed in children up to age 8 years (also resembling the findings for vowels) • In languages where voiced and voiceless consonant pairs are found, the voiceless one is acquired first • Stops are acquired before fricatives • Apical trills are acquired late • Affricates are acquired late (except in Cantonese) • When clusters are reduced, the later-acquired cluster member is deleted • This explains why, in English, stop + liquid clusters as well as /s/ + stop clusters are frequently reduced to the stop

Universal Trends in the Occurrence and Elimination of Phonological Processes Studies on phonological processes in typically developing children have been reported for English Examples for Portuguese are reported by Galea (this volume) Studies in other languages have not yet been published

Sidebar 9.1 So, what if some of your consonants are not accurate, anyway? The term lisp is used as an everyday term by the general public to indicate the non-conventional quality of a group of speech sounds, mostly sibilants. It is also used as a specific term by SLPs to indicate the perceived quality resulting from non-conventional articulation characteristics of certain speech sounds. Nowadays, English-speaking SLPs consider this speech phenomenon a treatment target. It is important to recognize that people throughout history have evaluated lisping and other speech impediments in various ways, depending on the historical context and cultural environment that served as background. For example, in Ancient Greece, Alcibiades (circa 450 BC – 404 BC), the famous Athenian statesman, orator and general who was a disciple of Socrates downright flaunted his lisping, and people of high standing thought it made his speech lovely and peculiar. Writings of Plutarch indicate that Alcibiades’ son even imitated his father’s speech production patterns. While lisping was considered erroneous speech production, Alcibiades was not working on remediation (Rose, 2003).

Connections In this chapter, general patterns of acquisition of vowels and consonants across many languageswere described. In particular, predictions based on a structural linguistics framework were evaluated in light of evidence from many languages More information about structural linguistics is found in Chapter 1 of this volume Specific information about the acquisition of the English phonological system is found in the chapters in Section II of this volume How monolingual children acquire the phonological systems of French, Brazilian Portuguese, and Korean is described in Chapters 10 through 12, respectively Chapters 13 and 14 focus on aspects of multilingual speech acquisition

Concluding Remarks • Vowel accuracy should be investigated with acoustic studies • Other areas that have not yet been investigated in depth: • Vowel durations • The effects of vowel duration, consonant environment, stress pattern, tone, and frequency in the language on vowel accuracy • Much remains to be discovered about cross-linguistic trends in speech sound acquisition

Chapter 9 Cros s-Linguistic Trends in the Acquisition of Speech Sounds