When speaking naturally and counting syllables, I pronounce ‘tales’ and ‘tells’ largely the same; the vowel in the first is longer and slightly higher (/e:/ vs /ϵ/). But when emphasizing (‘not tells, TALES’), I would do more like your ‘tay-uls’.
When speaking naturally and counting syllables, I pronounce ‘tales’ and ‘tells’ largely the same; the vowel in the first is longer and slightly higher (/e:/ vs /ϵ/). But when emphasizing (‘not tells, TALES’), I would do more like your ‘tay-uls’.