Such phenomena are due to
the phonemic inventory of the Thai language. Different languages distinguish
different sets of phonemes as the minimum sound units that distinguish meaning
among words. Thus for Japanese, for example, since they do not distinguish between
the sound [r] and [1] , they tend to have the problem distinguishing these two sounds
when learning English. In a similar vein, native speakers of English also have
problem distinguishing between "mother" and "horse" when learning Chinese, for
native speakers of English do not make differences among the four tones in Chinese.