The discrimination of speech sounds within and across phoneme boundaries.

In listening to speech, one typically reduces the number and variety of the many sounds with which he is bombarded by casting them into one or another of the phoneme categories that his language allows. Thus, a listener will identify as b, for example, quite a large number of acoustically different sounds. Although these differences are likely to be many and various, some of them will occur along an acoustic continuum that contains cues for a different phoneme, such as d. This is important for the present study because it provides a basis for the question to be examined here: whether or not, with similar acoustic differences, a listener can better discriminate between sounds that lie on opposite sides of a phoneme boundary than he can between sounds that fall within the same phoneme category. There are grounds for expecting an affirmative answer to this question. The most obvious, perhaps, are to be found in the common experience that in learning a new language one often