Do these spellings reflect pronunciation?

One time I came across a sentence that said something along the lines of "Having walk up the stairs each time was a real announce". It took quite a bit of puzzling to figure out what was meant. I won't spoil your fun by telling you.

Another example is "definately". Are these people just bad spellers, or are they reflecting their accents in the spelling? And if this is reflecting pronunciation, how does that work? I mean, I'll see situations where the standard accent pronounces [letter1] as [vowel1] and [letter2] as [vowel2], but a regional accent pronounces [letter1] as [vowel2]. People with that accent will then spell a word with [letter1] as [letter2]. Why? If they pronounce the word with [vowel2], and they think of [letter1] as recording [vowel2], why aren't they writing [letter1]?

One of the phonetic environments which greatly affects F2 is that of a following /l/. The
fact that /oh/ is more common than /o/ in the position before /l/ may be the single biggest
reason why a naive acoustic analysis of a sample of connected speech will usually show a
low back distinction, regardless of whether it really exists.

The first example was probably the result of the writer making a typo and then choosing the wrong spellchecker suggestion. The common misspelling "definately" is probably the result of words like "obstinate" where the "nate" is pronounced the same as the "nite" in "definite". I doubt it reflects the speaker's accent.

A lot of people are just crappy spellers. Or crappy typists, like me.

You would pronounce "definately" and "definitely" the exact same way -- sort of as "definetly". There are a lot more -ate words pronounced that way than -ite words, which usually get a long I sound. So the spelling itself is a little troublesome.

Same with another commonly misspelled word: separate. Often spelled as "seperate", which is how it is pronounced, because that middle syllable is more of a schwa, or sometimes not even there.

People of all dialects seem to do this -- I've caught Americans, British people, and Australians screwing these words up. There aren't a lot of variations in how they are pronounced from country to country, either, that would make one spelling make more sense than another.

Announce for annoyance is just a major mistake, and not one I've ever seen before.

the worst examples: pleasent vs pleasant and messenger vs messanger.

Yeah, errors like "definate" and "separate" (as well as "existant" and others) result from unstressed vowel reduction in English, and would be pretty common in all dialects.

"separate" is not an error. I assume you meant "seperate".

Sometimes it's hard to misspell on purpose!