The problem with calling an apostrophe a letter is that in standard usage, it doesn't change how you read (prosody) or pronounce the text. Sometimes it's used i

The problem with calling an apostrophe a letter is that in standard usage, it doesn't change how you read (prosody) or pronounce the text. Sometimes it's used in transliterating foreign words to indicate a glottal stop (an actual sound!) or as a syllable divider, but that's not really English at that point.