I tend to think of this in terms of compression: you can use various compression schemes to store english words in fewer bits, but that will make you store foreign words in more bits. For example, you could order letters by frequency and represent frequent letters with fewer bits. You can do the same with groups of letters (e.g. “thing” = “th” + “ing”, both very frequent combinations in English), or take advantage of conditional probabilities (‘t’ much more likely to be followed by ‘h’ than ‘n’) to squeeze a few more bits of compression. Similarly, if a westerner wanted to describe the Chinese character 語 without any prior knowledge of Chinese, the description would be very long, but a Chinese speaker would describe it as “the key for speech, and a five above a mouth”.
This is just another way of describing what you call phonetic space.
Simple issues of frequency makes learners see words as “closer” than native speakers do, another problem is when the “phonetic space” of one language has more(or different) dimensions than those of another; e.g. many people find it hard to learn words when the distinction between voiced and unvoiced “th” is important, or when the tone of a syllable also carries meaning (as in Chinese). The Chinese words for “mother”, “insult” and “horse” all sound like exactly the same word, “ma”, to non-Chinese speakers.
I tend to think of this in terms of compression: you can use various compression schemes to store english words in fewer bits, but that will make you store foreign words in more bits. For example, you could order letters by frequency and represent frequent letters with fewer bits. You can do the same with groups of letters (e.g. “thing” = “th” + “ing”, both very frequent combinations in English), or take advantage of conditional probabilities (‘t’ much more likely to be followed by ‘h’ than ‘n’) to squeeze a few more bits of compression. Similarly, if a westerner wanted to describe the Chinese character 語 without any prior knowledge of Chinese, the description would be very long, but a Chinese speaker would describe it as “the key for speech, and a five above a mouth”.
This is just another way of describing what you call phonetic space.
Simple issues of frequency makes learners see words as “closer” than native speakers do, another problem is when the “phonetic space” of one language has more(or different) dimensions than those of another; e.g. many people find it hard to learn words when the distinction between voiced and unvoiced “th” is important, or when the tone of a syllable also carries meaning (as in Chinese). The Chinese words for “mother”, “insult” and “horse” all sound like exactly the same word, “ma”, to non-Chinese speakers.