George Bernard Shaw claimed, tongue in cheek, that the word fish could be spelled “ghoti.”
gh = /f/ as in enough. o = /i/ as in women. ti= /sh/ as in nation.
True, these sounds can be spelled in these ways, but never in this way.
In English, there is not one single word in which the letters gh are used to start a word having the /f/ sound. Nor is there a single word ending with the /sh/ sound spelled ti. However, the sound “fish” is always spelled “fici” in words whose base has more than one syllable.
As a matter of fact the sound /fish/ is spelled fish only in words that can be reduced to a base (morpheme) of one meaningful syllable. The words fish, fishes, fished, fishing, fisherman, fishermen, fishery, and fisheries can all be reduced to “fish.” The sound /fish/ happens to always be spelled fici in words that have a base of more than one syllable. For the phonic patterns rarely taught in schools see The Fancy Words.
We say “uh fish ul” but we spell official.
We say “ben uh fish ul” but we spell beneficial.
We say “ee fish unt” but we spell efficient.
We say “suh fish unt” but we spell sufficient.
In “A fisherman is fishing” the base is
fish which has only one syllable.