A Latin or Roman alphabet is one of many alphabets that use the letters of the Latin script. These letters formed the basis of the original Roman Latin alphabet. Some letters of the Latin script were altered slightly for use in particular languages, although the main letters are largely the same. There were several general types of alterations made to extend the alphabet's uses, depending on the language: diacritics could be added to existing letters; two letters could be fused together into ligatures; additional letters could be inserted; or pairs or triplets of letters could be treated as units (digraphs and trigraphs).