There are varieties of English, but I'm talking about standard English English.
Male, tail, tale have the same sound.
Mile and tile have the same sound.
Some southern English accents pronounce the 'a' sound in 'male' rather like the 'i' in 'mile'. I'm thinking especially of 'cockney' and its more recent variants.
What do you mean when you talk about "mayo"? I can think of two ways of saying that. One is 'my o' and the other is 'may o': I suppose it depends on how one says 'mayonnaise'. It's a French word. I have no idea why anybody would pronounce it 'my-onnaise'.
More extensive L-vocalization is a notable feature of certain dialects of English, including Cockney, Estuary English, New York English, New Zealand English, Pittsburgh, Philadelphia English and Australian English, in which an /l/ sound occurring at the end of a word (but usually not when the next word begins with a vowel and is pronounced without a pause) or before a consonant is pronounced as some sort of close back vocoid: [w], [o] or [ʊ]. [...] It can be heard occasionally in the dialect of the English East Midlands, where words ending in -old can be pronounced /oʊd/. KM Petyt (1985) noted this feature in the traditional dialect of West Yorkshire but said it has died out. However, in recent decades, l-vocalization has been spreading outwards from London and the south east
That's an idea, Loob.
I wonder if that's the same as 'dark' and 'light' L. 'Pearl' is the word I think of for dark L at the end. The 'dark L' in the wrong place is a notable feature of a Russian accent.
I most definitely don't say it at the end of 'mail'. Actually I find it hard to say.
And while some speakers may use a vowel (something like [o]) or a [w] sound at the end of 'mail', instead of any kind of [l], those speakers still always distinguish 'mail' and 'mayo'. There is always some difference between the two, for all speakers, regardless of the details of how they make them.
For what it's worth, there's a distinct difference between the pronunciation of "mail" and "male" in the subcontinent (and perhaps in other parts of Asia too). The vowel sound in mail is a diphthong, while that in male sounds like the last syllable of resume (as in a CV - I don't know how to get the accent on the e).