Don't know what you call these, we call all four of them consonants.

goofy is making a distinction between the actual sounds (phonemes) of English and their written representation. Some languages go for a one-to-correspondence between these two things, and others go for a many-to-one or one-to-many.

For example, the single sound represented by the IPA symbol /ʃ/ is normally written in English as {sh} and in German as {sch}, but Czech gets away with a single letter {š}. IPA ʒ can be a single symbol as in English garage or French je 'I', but two in Hungarian {zs]as in rozsa 'rose'. OTOH, IPA /ju/, which are two sounds, is a single letter in English human.

Ceci n'est pas un seing.