The Portuguese alphabet contains twenty-four letters, being the same as the English, with the exception of K and W, Which are not in their alphabet.
The tittle, or little dash, which the Portuguese call til, is set by them over some letters instead of m; as bẽ instead of bem; y convẽ instead of convem; hũa instead of huma.
They also set their til ~ over the vowels ao, aa, in the end of words, thus aõ aã. .
It may be observed that the curved mark ~ is the most perfect, though it is found necessary, in English types, frequently to substitute the plain - instead of the curved. — Vieyra's Portuguese Grammar, 9th edit.