The Iowa Articulation Norms Project and its Nebraska Replication

Abstract

The purpose of the Iowa Articulation Norms Project and its Nebraska replication was to provide normative information about speech sound acquisition in these two states. An assessment instrument consisting of photographs and a checklist form for narrow phonetic transcription was administered by school-based speech-language pathologists to stratified samples of children in the age range 3-9 years. The resulting data were not influenced by the demographic variables of population density (rural/urban), SES (based on parental education), or state of residence (Iowa/Nebraska); however, sex of the child exerted a significant influence in some of the preschool age groups. The criteria used to determine acceptability of a production appeared to influence outcomes for some speech sounds. Acquisition curves were plotted for individual phoneme targets or groups of targets. These curves were used to develop recommended ages of acquisition for the tested speech sounds, with recommendations based generally on a 90% level of acquisition. Special considerations were required for the phonemes /ng s z/.

A highly penetrant form of childhood apraxia of speech due to deletion of 16p11.2

“…Called "protowords" (Menn, 1978) or "phonetically consistent forms" (Dore et al, 1976). ;11 takes first steps 1;1 uses common objects appropriately 1;2 picks up small objects with thumb/finger 1;3 builds tower of 3-4 blocks 1;4 scribbles lines on paper 1;5 walk and run unassisted 1;6 walks up stairs 1;7 catches ball crudely 1;8 scribbles in circles 1;9 jump lifting both feet off the floor 1;10 climb, squat, kick a ball 1;11 put shoes on part way 2;0 turn book pages 2 or 3 at a time (McLaughlin, 1998) 2;0 -3;0 years "Unlike toddlers, preschoolers develop more freedom of movement and therefore, soon become trailblazers in every sense of the word" (McLaughlin, 1998, p. 271 /p√/= 3.7 per second; /t√/ = 3.7 per second /k√/ = 3.65 per second; patticake = 1.26/sec (Robbins & Klee, 1987) Maximum phonation time 2;6 -2;11 = 5.55sec (Robbins & Klee, 1987) A C Q U I R E D S O U N D S Consonants (females) Smit, et al, 1990) 2;0 = /m, n, h, g/ 2;6 = + / p, N, w, t, d, k/ 3;0 = + / j, f/ (Chirlian & Sharpley, 1982) Kilminster & Laird, 1978) Consonants (males) Smit, et al, 1990) 2;0 = /m, n/ 2;6 = + / N, d/ 3;0 = + / p, b, h, w, k, g/ (Chirlian & Sharpley, 1982) Kilminster & Laird, 1978) Consonant clusters "Two-year-old children can produce consonant clusters, but these may not be of the same form as the ambient language" (McLeod, van Doorn & Reed, 2001a).…”

“…There is also a simplification process that seems to be more prevalent in these children than in their language level controls, namely, the deletion of unstressed syllables, mainly initial ones." (Aguilar-Mediavilla, Sanz-Torrent, & Serra- Raventos, 2002, p. 573) 3;0 -4;0 years "A client 3 years of age or older who is unintelligible is a candidate for treatment" (Bernthal & Bankson, 1998, p. 272 3;6 = + / k, f / 4;0 = as above (Kilminster & Laird, 1978) Consonant clusters 3;6 (males & females)= /tw, kw/ 4;0 (females) = /tw, kw, pl, bl, kl/ 4;0 (males) = /tw, kw/ (Smit, et al, 1990) 4;0 = /tw, kw, sp, st, sk, sm, sn, pl, bl, kl, gl, pr, br, tr, dr, kr, gr/ (Templin, 1957) Vowels Paradigmatic production (ie production of individual vowels) is generally mastered by 3 years. However, syntagmatic production (production of vowels in context such as polysyllabic words) takes up to at least 6 years (James, van Doorn & McLeod, 2001) P E R C E N T C O R R E C T Consonants 3;0-3;11 = 76.77% in monosyllabic words 3;0-3;11 = 76.41% in polysyllabic words (James, van Doorn & McLeod, 2002) 3;5-3;11 = 85.2% (Waring, Fisher, Atkin, 2001) Consonant clusters 3;5-3;11 = 86.4% (Waring, Fisher, Atkin, 2001) Vowels (Australian) 3;0-3;11 = 94.9% in monosyllabic words 3;0-3;11 = 88.28% in polysyllabic words (James, van Doorn & McLeod, 2001) Vowels (American -nonrhotic) 3;0-3;5 = 97.3% (range = 89-100) 3;6-3;11 = 97.2% (range = 91-100) (Pollock, 2002;Pollock & Berni, 2003) Vowels (American -rhotic) 3;0-3;5 = 79.2% (range = 4-100) 3;6-3;11 = 76.5% (range = 4-100) (Pollock, 2002) …”

“…Emerging skills (Dodd & Gillon, 2001) (James, 1990, p. 74 Smit, et al, 1990) 4;0 = / m, n, N, d, p, b, h, w, k, g, j, t, f, l, S, tS, dZ, s/ 4;6 = + /Z/ 5;0 = + /r/ (Chirlian & Sharpley, 1982) 4;0 = /h, N, p, m, w, b, n, d, j, g, Z, k, f / 4;6 = /t, l, S, tS, dZ/ 5;0 = /r/ (Kilminster & Laird, 1978) Consonant clusters (all children) kw, sp, st, sk, sm, sn, pl, bl, kl, gl, pr, br, tr, dr, kr/ 4;6 = /tw, kw, sp, st, sk, sm, sn, pl, bl, kl, gl, pr, br, tr, dr, kr, gr, fr/ 5;0 = /tw, kw, sp, st, sk, sm, sn, pl, bl, kl, gl, fl, pr, br, tr, dr, kr, gr, fr, str/ (Templin, 1957) Consonant clusters (females) 4;0 = /tw, kw, pl, bl, kl/ 4;6 = /tw, kw, sp, st, sk, sw, pl, bl, kl, gl, fl, kr, skw/ 5;0 = same as for 4;6 (Smit, et al, 1990) Consonant clusters (males) 4;0 = /tw, kw/ 4;6 = /tw, kw, gl/ 5;0 = /tw, kw, sp, st, sn, bl, gl, dr/ (Smit, et al, 1990) Vowels Paradigmatic production (ie production of individual vowels) is generally mastered by 3 years. However syntagmatic production (production of vowels in context such as polysyllabic words) takes up to at least 6 years of age.…”

Individual differences in the influence of phonological characteristics on expressive vocabulary development by young children

“…For the independent age of acquisition, the earliest age when 50% of 15-to 39-month-old children's phonetic inventories included the sound was determined from Stoel-Gammon (1985) and Dyson (1988). For the relational age of acquisition, the proportion of 3-year old children who correctly articulated each consonant was obtained from the data by Smit, et al (1990).…”

Speech characteristics of 8-year-old children: Findings from a prospective population study

“…While normative data on single word production for children of this age are available (Chirlian & Sharpley, 1982;Craig, Thompson, Washington & Potter, 2003;Haynes & Moran, 1989;Kilminster & Laird, 1978;McLeod & Arciuli, 2009;Roberts, Burchinal & Footo, 1990;Smit, Hand, Freilinger, Bernthal & Bird, 1990), to date there have been no studies which have provided population data for older children across different sample types. Moreover, studies of PSD have typically used small clinical samples rather than reference to a normative dataset.…”