English vowels front central back high i u   mid e o E   low  A  North Atlantic English (UK, Ireland): front central back unrounded rounded high i u lower-high   mid higher-mid e o lower-mid E   low  A  Quantity and quality are interrelated in English. It’s true that the high vowels are longer and more peripheral in the vowel space than the lower-high. And this is also true of [e] vs. [E] and [^], but not really true of [o] vs. [O].

English vowels A speaker from Southern England: lower-high lower-mid front central back unrounded rounded high [bid] bead [bud] booed lower-high [bd] bid [bdst] Buddhist higher-mid [bed] bayed [bod] bode lower-mid [bEd] bed [bd] bud [bd] bawd low [bd] bad [bAd] bard [bA] bah [bdi] body

English vowels Sound changes in N. America. What happened to []: ,  > (‘merged as’)  (East) []: body, bawd, []: bah ,  >  (East, Midwest) []: body, bah, []: bawd , ,  > A (West) []: body, bah, bawd [] was historically a lax vowel. [] and [] were historically tense vowels. When [], [] merge, is the result a tense or lax vowel? This is why the tense/lax distinction breaks down as a result of dialect-specific mergers.