Old English dental fricatives??

Question

Why are Old English dental fricatives voiceless at the beginning and end of words?
In Modern English words like "the" and "this" the interdental is voiced due to assimilation.
Is there some kind of linguistic process which dictates that Old English dental fricatives at the beginning and end of a word must be voiceless?

Answer 1

English has lost its original verb inflections. When the stem of a verb ends with a dental fricative, this was usually followed by a vowel in Old English, and was therefore voiced. It is still voiced in modern English, even though the verb inflection has disappeared leaving the /ð/ at the end of the word. Examples are to bathe, to mouth, to breathe. Often a remnant of the old inflection can be seen in the spelling in the form of a silent ; viewed synchronically, this may be regarded as a marker of the fact that the fricative is voiced.

Answer 2

The first general tendency that leaps to mind is for 'underlyingly' voiceless consonants to become voiced when they appear between vowels. Thus one might think the language has just one phoneme, the voiceless interdental fricative, which has a conditioned allophone, the voiced one.

However, it is also common for Germanic and Slavic languages to make word-final consonants voiceless. This means that if the language happened to have two distinct phonemes, the voiceless and the voiced interdental fricative, you would never know it from looking at the last consonants of words, would you (falling intonation), because the contrast between voiced and unvoiced phonemes would be neutralized in that environment.

So before you chase around for a plausible rule governing the voicing/devoicing of these segments, you need to find out which of them is 'basic', or indeed whether both are phonemic. You seem to assume that there is just one phoneme and that it is unspecified for voice, a non-phonemic feature that it picks up in the intervocalic environment only. Could be too. Start by establishing the phonemic inventory; then look for historical or phonotactic reasons for the distribution of the alleged allomorphs.

Answer 3

I don't know the exact answer to this question, but I think you might be thinking about it backwards... remember that Old English came before Modern English. I'm not so sure that the voicing on them nowadays can be explained by assimilation... could you explain more about that? I'm assuming you're thinking that they are voiced when followed by a vowel, but what about words like "thought", which has a voiceless interdental before a vowel?

P.S. Yahoo! Answers is a terrible place to ask questions like this because there are only a few people on here who have enough training to understand, let alone answer, this question. I'm assuming you're a linguist; you might want to ask other linguists you know, or LINGUISTList.