SomehowGeekyPolyglot wrote:What are some possible effects of using some rather uncommon words, does it hinder communication, or are there also many people who appreciate it because it fuels their curiosity?
It depends entirely on the context, doesn't it? If you were explaining something to kindergarteners, you'd use different words than if you were having a conversation with people you met through your mutual interest in that subject. It may be kind of patronising to choose your words depending on the listener, but I'm pretty sure the vast majority of people do that at least subconsciously.
If it's a word relevant to the subject at hand and the other person shares your interest in said subject, it seems logical to assume they know what it means (or will either look it up or ask you if they don't), but if it's a totally random obscure word that has no relevance to the conversation, isn't that kind of pointless and annoying?
SomehowGeekyPolyglot wrote:This is about things like pronouncing the TH as in "thank you" as a T and some more.
But that's not only "African English". I'm not exactly sure which parts of the US and UK (and elsewhere) have that as the default, but for many non-native speakers whose first language lacks /θ/ and /ð/, it's pretty much the default by default. Of course there's the issue of vowels and the pronunciation of /r/ and everything, and I'm not questioning the very real possibility that your accent includes all of the features of stereotypical "African English" since you'd have no reason to lie about that (and it could be that you've been exposed to English as spoken by Africans more than English as spoken by non-Africans, and as such it's your default), but...
...for example, Finnish English is definitely not "African" even though we stereotypically tend to pronounce /θ/ and /ð/ as [t̪] and [d], either both /ɒ/ and /ʌ/ as [ɑ~ɑ̟~a̠] or as [o̞] and [ɑ~ɑ̟~a̠] respectively, /r/ as [r~ɾ], etc. like people in a lot of African countries. That's not to say that all Finns pronounce them like that, either, since not everyone speaks "rally English"; some have the most American [ɻʷˤ] and [θ] and [ð] and whatnot, which is the "ideal", but sounding "too American", especially when it comes to vowels, is still generally seen as a bad thing AFAIK.