Expressive vocabulary word categories of children who are deaf and hard-of-hearing

Abstract

This study investigated the acquisition of early expressive vocabulary among young children who are deaf and hard-of-hearing (DHH; n = 68) using auditory technology (hearing aids and cochlear implants). Parents completed a standardized vocabulary checklist, which allowed analyses of (i) the size of their child's spoken vocabulary; (ii) composition of the expressive lexicon (e.g., parts of speech such as nouns and verbs; semantic categories such as routines and body parts); and (iii) demographic and audiologic factors (e.g., chronologic age, degree of hearing access) potentially associated with these metrics. Young children who are DHH and use auditory technology acquired fewer spoken words than peers with typical hearing (TH) matched for chronologic age but more spoken words than peers with TH matched for listening experience. Action verbs-not nouns-significantly increased the odds of a child who is DHH achieving a vocabulary quotient within the normative range. These findings support the exploration of early expressive vocabulary size and composition-especially the number of active verbs-to guide clinical management and decision-making for young children who are DHH.

Keywords: deaf; early childhood; hard of hearing; listening technology; vocabulary.

Figure 1

This figure displays the mean number of words produced by children who are DHH and age-matched peers with TH, as measured on the MacArthur-Bates Communicative Development Inventory: Words and Sentences. The chronologic age spans the x-axis and the y-axis shows the mean number of words in the expressive lexicons. The sample size for each time interval (shown in parentheses next to chronologic ages on the x-axis) reflects the number of children contributing data to the DHH group, represented by the black columns. White columns represent total expressive lexicon for 45 children with TH and typical development from 21 to 30 months of age, as reported by Hadley et al. (2016). Hadley and colleagues did not report values for an 18-month interval. Error bars reflect standard deviation. Visual inspection suggests both groups increase the number of words produced, but the group with TH does so with larger lexicons and faster growth rates than the group who are DHH.

Figure 2

Figure 2 shows chronologic age in months on the x-axis and expressive vocabulary size, as measured on the MacArthur-Bates Communicative Development Inventory: Words and Sentences, on the y-axis. Older chronologic age coincides with larger expressive vocabulary size, r = .32, p = .02.

Figure 3

Figure 3 shows listening age in months on the x-axis and expressive vocabulary size, as measured on the MacArthur-Bates Communicative Development Inventory: Words and Sentences, on the y-axis. Longer duration of device experience corresponds with larger expressive vocabulary size in children who are DHH using hearing aids or cochlear implants, r = .46, p < .001.

Figure 4

In both panels of Figure 4, the x-axis shows chronologic age in months (with the number of participants at each interval in parentheses) and the y-axis displays the mean number of nouns (Figure 4a in the top panel) or verbs (Figure 4b in the bottom panel) produced, according to the MacArthur-Bates Communicative Development Inventory: Words and Sentences. The sample size for each time interval reflects the number of children contributing data to the DHH group. Black columns represent mean expressive vocabulary size for this sample of children who are DHH. White columns represent total expressive lexicon for 45 children with TH and typical development, as reported by Hadley et al. (2016). Hadley and colleagues reported data in three-month intervals between 21 and 30 months, but not for an 18-month-old time point. Error bars reflect standard deviation. (A) Figure 4a shows the mean number of nouns produced by children who are DHH and age-matched peers with TH. Visual inspection suggests both groups increase the number of words produced, but the group with TH does so with larger lexicons and faster growth rates than the group who are DHH. (B) Figure 4b focuses on the mean number of verbs expressed by young children, showing increased values with increased chronologic age but with a marked lag in verb lexicon compared to peers with TH.

Figure 5

(A) The top panel of Figure 5 shows chronologic age on the x-axis and the noun: verb ratio on the y-axis. Chronologically older children who are DHH have significantly larger noun:verb ratios than chronologically younger children who are DHH, r = .32, p = .02; (B) The bottom panel of Figure 5 displays listening age on the x-axis and the noun:verb ratio on the y-axis. No significant relationship exists between the duration of device experience and the proportion of nouns versus verbs in young children who are DHH, r = .21, p = .30.

Figure 6

The figure shows the distribution of the number of action verbs on the x-axis and the number of patients on the y-axis. The top panel displays the number of action verbs for children who are DHH with vocabulary quotients by chronologic age < 80, including participants for whom vocabulary quotients could not be calculated. The centre and bottom panels exhibit the number of action verbs produced by children with vocabulary quotients by chronologic age between 80 and 100 and those with vocabulary quotients by chronologic age > 100, respectively. Children with higher vocabulary quotients produce more action verbs.

Figure 7

The figure shows the distribution of the number of action verbs on the x-axis and the number of patients on the y-axis. The top panel displays the number of action verbs for children who are DHH with vocabulary quotients by listening age < 80, including participants for whom vocabulary quotients could not be calculated. The centre and bottom panels exhibit the number of action verbs produced by children with vocabulary quotients by listening age between 80 and 100 and those with vocabulary quotients by listening age > 100, respectively. Children with higher vocabulary quotients produce more action verbs.