It would have to depend on what language you're trying to transliterate, because the phonetic meaning of the Latin letters is different depending on the language they're used to represent (and for many languages, depending on the particular word). For example, ti- will usually be /tʃi/ in Brazilian Portuguese and /tɪ/ in English. Typically each orthography is specific to a language and a script doesn't encode sounds in a consistent language-independent way, so you have to know something about both the source and target languages to devise a transliteration system.