So, I love phonetics and dialectology. I'm really surprised that there doesn't yet appear to be a thread where people discuss their regional dialects or particular idiolects, considering how many linguistics nerds there are here. I thought I'd share a bit about the Southern US dialect here in Georgia, although I speak much closer to SAE as my parents are from the North. So, here are some interesting bits about the local variety of English:
Pen pin merger - I'm sure you've all heard about this one, and it still makes me laugh when people become angry with Southerners because of this
For those of you who don't know, the vowels /ɛ ɪ/ aren't very distinct in most parts of the South. In a few environments (such as preceding a nasal consonant), /ɛ/ often merges to /ɪ/ so that pen and pin are homophonous as [pɪn]. Similarly, "gem" is homophonous to "Jim" as [dʒɪm]. The same is true for "any" as it is pronounced [ɪni] rather than [ɛni]. In my experiences, most of my acquaintances who speak Southern English can't even perceive the difference between [dʒɪm] and [dʒɛm], which I find fascinating. Although I can hear the difference just fine, my spoken English uses the /ɪ/ forms exclusively, unless I'm speaking to someone who is bothered by it 
Crazy /æ/ - Many rural speakers here pronounce /æ/ as something similar to /æjə/ so that "cat" becomes [kæjət]. My speech doesn't contain this feature, maybe because my parents would have killed me if I had started talking like this as a child
Glottal stops - I've been told this isn't just a Southern thing, but I feel that Southern speakers do this more than speakers from other regions. Rather than just using an allophonic glottal stop in place of a /t/ for words like "button" [bʌʔn] (syllabic n), it shows up in other places like "mountain" [mɑʊnʔn] (second /n/ being syllabic) or "hadn't" [hæʔnt] (glottal stop replaces /d/, syllabic n, and unreleased /t/). I think there's always an /n/ involved that becomes syllabic due to the elision of a vowel.
Especially - Quite a few speakers here say [ɛkˈspɛʃəli] rather than [əˈspɛʃəli], [ɪˈspɛʃəli], or [ɛˈspɛʃəli]. I have no idea where it comes from, honestly, other than maybe it was influenced by the pronunciation of "espresso" as "expresso." I personally say [əˈspɛʃəli], but [ɛˈspɛʃəli] sounds fine to me too. The other two pronunciations strike me as odd.
Etcetera - "Standard" American pronunciation is supposedly [ɛt sɛɾɚə], but many speakers here say [ɛk sɛɾɚə], reminiscent of the "ekspecially" pronunciation above.
Clothes - Clothes and close are homophonous as [kloʊz], because honestly, it's so much easier to say
I think this is an American English thing, but there are a good number of American speakers who retain the [kloʊðz] pronunciation, and they mock us at every turn.Sequentially - According to dictionaries, the "standard" pronunciation for this word should be [sɪkwɛnʃəli], but many speakers I've encountered say [sɪŋkwɛn̠ʧəli]. Why? Nasal epenthesis?
Immediately - This one is quite interesting, but it's pretty rare. Rather than [ɪmiɾiətli], some people here say [ɪmiɾiəntli], with a nasal consonant preceding the coronal stop. Why? Another case of nasal epenthesis?
Adaptation and Ambiguity - I'm not even sure how to classify these, but rather than [æ.dəp.teɪ.ʃən] and [æm.bɪ.ˈgju.ɪ.ɾi], I've heard people say [ə.dæp.ʃən] and [æm.ˈbɪ.gwɪ.ɾi]. "Adaption" seems to be a word in its own right, but when I asked people to spell the word they had just said, they spelled it as "adaptation," so they weren't thinking of the word "adaption" to my knowledge. As for ambiguity... I have no idea. I should ask those speakers how they pronounce "ambiguous" perhaps?
Cicada - These bugs are normally called [sɪˈkeɪdə] or [sɪˈkɑːdə], but here many people call them katydids [keɪɾidɪdz]. I had never actually heard this until about a month ago, and some people are telling me it's SAE? I don't think so, considering everyone I grew up with called them cicada.
Now for my personal idiolect. These are words I've been called out on before, and I've only found a few (or no) people who pronounce them as I do.
Ostrich - ['ɑ.stɹɪdʒ] or ['ɑ.stɹədʒ] After checking every English word ending in "ch," only Ostrich and Spinach word final "ch" become voiced for me.
Spinach - [spɪnɪdʒ] or [spɪnədʒ] I've read that this may be a British pronunciation?
Onion - [ˈʌŋ.jən] or [ˈʌŋ.jɪn] I've never found anyone else who pronounces onion in this manner. I have no idea where I picked it up.
Months - [mʌns] Where did my θ go?! My pronunciation may also be transcribed as [mʌnts], depending on who you ask.
Resourceful - [ɹəˈzɔɹsfəl] While I feel that my schwa in the first syllable is relatively normal for American dialects, the voiced /z/ but retention of voiceless /s/ in "resource" strikes me as interesting. There are a few other speakers I've found who use these pronunciations.
Australia - [ɑl.ˈsʧɹeɪl.jə] Intrusive L? Haha.
Problem - [pɹɑlbləm] Same as the above for 'Australia'.
Put - [pʊɪt] My [ʊ] vowel seems to be a diphthong [ʊɪ]. Praat spectrogram analysis seems to confirm my suspicions.
On a lexical note, I say neither refrigerator nor fridge. I say refridge [ɹəˈfɹɪdʒ]. No clue why.
I invite you all to share your local dialects and idiolects here
As linguists, we all know that no dialect or pronunciation is better than any other, but that doesn't mean we can't poke fun at ourselves for "sounding funny" if we do! I encourage that we use IPA, as trying to spell out sounds probably won't work out very well, as readers of xkcd come from very, very diverse language and dialectal backgrounds. Also, should you ever say "A sounds like B" or something along those lines, please include pronunciation information for both, as something that rhymes in your dialect may or may not rhyme in ours 
. Only recently I discovered there are a lot more silent consonants in starting consonant clusters than the k in kn-, e.g. w in wr-, p in ps- and m in mn- ... I try to pay more attention to this now.
