Númenórean Sindarin
From Tolkien Gateway
Gondor Sindarin was a dialect of the Elven language spoken by the Dúnedain of the South.
Sindarin was spoken by the nobility of Gondor, but many names were used in everyday speech, pronounced in their own way.
Since Westron did not possess the sound ch frequent in Sindarin, Gondorians pronounced it as light h, as in the case of Rohan(d), a word which an Elf would pronounce properly as Rochan(d).[1]
It is notable also that Gondorians did not pronounce the Sindarin vowel y properly, but understood it as a simple i instead[2].
Whatever other variations in pronunciation or grammar, must have existed, but nothing else is known.