The McGraw-Hill Online Learning Center says, "When you hear Japanese-born people speak English poorly, they make similar mistakes. Why?
Japanese characters are a staple on American TV, and so most Americans are familiar with what a "Japanese" accent is like. More specifically, we are familiar with the speech patterns of native Japanese speakers when they learn English later in life. One common mispronunciation is confusing the "r" sound and the "l" sound such as in "craw" and "claw." This mispronunciation is made because there is no distinction between the "r" sound and the "l" sound in Japanese. Linguists refer to these sounds as phonemes, and would talk about the r and l phoneme as /r/ and /l/. These sounds are actually very closely related, and it is only through training and the fact that the sounds are important for distinguishing between the meanings of certain words that English speakers learn to differentiate between them. As it turns out, English has about 35 phonemes, but there are many phonemes not used in English that native English speakers have a hard time recognizing. For example, native English speakers have a hard time hearing the difference between the [ph] in pin and the [p] in spin which is important in Hindi (spoken in India) or Sesotho (spoken in South Africa)."
Correction: Sesotho is spoken in South Africa and in Lesotho! I demand recognition for Lesotho. Hey, can you hear me? Hello?
Back to the post. This phenomenon can be seen in the following words:
The difference also exists with [t] and [th] sounds.