Résumé
Relative frequencies of occurrences of various sounds are very useful information in the field of communication disorders : functional articulation disorders, or organic articulation disorders such as dysarthria, apraxia of speech etc. Frequencies of occurrences of vowels, tones, initial and final consonants were studied. The recording tape of five-minute general daily life conversations of 64 graduate students were decoded and analysed. The results showed that the average number of syllables spoken in a 2-student conversation is 69.85 syllables/minute. The most frequently occurring sounds in the Thai language were /k/, /_n/, /ai/ and mid tone. On the other hand the least frequently occurring sounds were /f/, /_p/, /iu/ and rising tone. The Spearmann rank order correlation coefficient of this result and the previous studies are 0.8753 and 0.8935 (p<0.001). The order of frequencies of occurrences of sounds were the criteria for determining which sound to correct first and also useful to assess, treat and it could be developed to be a passage which is the tool for evaluation.