Development of Persian Lexical Neighborhood Tests

Spoken word recognition (SWR) is a complicated process whereby through listening to a word or sentence we automatically connect each word's acoustic signal to its stored representations in the mental lexicon. We hypothesized that the children's performance on SWR would be influenced by the lexical difficulty and word length. The aim of the study was to develop the Persian Lexical Neighborhood Tests (PLNTs) as a lexically controlled toolkit based on the Neighborhood Activation Model to measure the SWR of Persian-speaking children.

The research project was carried out in two phases (Weber and Scharenborg, 2012) [1]: development of the PLNTs (Luce and Pisoni, 1998) [2]; Using PLNTs in children with normal hearing. In Phase 1, to determine the lexical difficulty of words (easy, hard, and neutral), we calculated word frequencies and neighborhood densities for the words elicited from the 461 well documented language samples of Persian-speaking children aged 2-5 years old. Accordingly, four lexically controlled words subscales were generated by selecting appropriately easy and hard key words include: Persian Monosyllabic Lexical Neighborhood Test (PMLNT)-easy, PMLNT-hard, Persian Disyllabic Lexical Neighborhood Test (PDLNT)-easy, and PDLNT -hard. In Phase 2, The PLNTs were performed by sound field at different levels of signal to noise ratio (SNR) on twenty children with normal hearing between the ages of 6-12 year.

The participants performed significantly better on SWR using the PLNTs consisting of easy words compared to the PLNTs consisting of hard words and using disyllabic words compared to monosyllabic words. Moreover, the participants' performance on SWR improved overall with increasing the SNR levels.

The PLNTs is a lexically controlled assessment toolkit independent of vocabulary and language competency that can be used to measure the SWR performance in Persian-speaking children under spectrally degraded conditions.