In some dialects, such as Canadian English and certain regions of the UK, a vowel is noticeably shortened before an unvoiced consonant (/s/ and /f/ in your 2 examples, as compared to a voiced final consonant, as in I've and hive. In others, this phenomenon is less pronounced. So you may hear a really long, drawled out /aI/ in ice / life, but you may hear quite a clipped, short version of the vowel, with less obvious diphthong quality.
This is in fact the main difference between AmE and CanE: We even say "out", "about" and 'house" with a shortened diphthong, much shorter than our American cousins, but we pronounce "loud" and "vows" the same way they do.
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