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.