The limitations of transliteration into Latin characters
I'm working on my first conlang, a proto-language for a few of the languages spoken by characters in my current writing project. I suddenly feel how inadequate Latin orthography is for expressing phonemes that are foreign to native speakers of English and other Western European languages (sorry, Mandarin and Cantonese!). Who knew that there could be such ramifications associated with the choice of a letter. For example, I somehow had the brilliant idea of making both the un-aspirated "p" and the aspirated "pʰ" phonemic. Now I'm at a loss as to how to express this difference in English letters. "Ph" would be taken to be "f" and "pk" or "px" wouldn't produce the correct sound. "Pp" would be an idea except for the fact that it would make it appear as though the "p" sound were phonemically longer than it really is, as in Proto-Finnic and modern Estonian. I've looked over the diacritic section of the IPA to see if there might be something that I could use, but other than the superscript "h", there is not. Would some sort of slash through the lower stem of the "p" work? That seems to be the only thing that is suggesting itself to my mind.
This is just one of the challenges presenting itself to me with transcribing the phonology of my conlang.