Abstract
The study examined the use of MLU and IPSyn in Czech including their validity against test-based measures of vocabulary and grammar comprehension. We developed a Czech version of IPSyn and we compared the scores with MLU in syllables, morphemes, and words in the same transcripts.
We used a corpus of 110 children recorded at two time points: 2;6 and 4;11. The different MLU measures correlated closely (r's > 0,97).
We found strong correlations between MLU and IPSyn in both time points (0.88 and 0.77). In regression analyses, MLU and IPSyn in 2;6 years had a significant unique effect on the later scores of these measures (ß = 0.35 and 0.37, respectively).
For IPSyn, the vocabulary test showed a unique predictive effect above the factors of other predictors (ß = 0.26). Our results confirm that MLU in words is an adequate measure.
IPSyn is a valid measure since it predicts itself in time with a vocabulary measure as a unique predictor and it also correlates closely with MLU.