Morpho-phonemic orthography

A phonemic orthography is an orthography (system for writing a language) in which the graphemes (written symbols) correspond to the phonemes (significant spoken sounds) of the language. Languages rarely have perfectly phonemic orthographies; a high degree of grapheme-phoneme correspondence can be expected in orthographies based on alphabetic writing systems, but they differ in how complete this correspondence is. English orthography, for example, is alphabetic but highly nonphonemic; it was once phonemic during the Middle English stage, when the modern spellings originated, but spoken English has since changed while the orthography has remained constant, resulting in the modern nonphonemic situation. However, because of their relatively recent modernizations when compared to English, the Italian, Turkish, Spanish, Finnish, Czech, and Polish orthographic systems come much closer to being consistent phonemic representations.

In less formal terms, a language with a highly phonemic orthography may be described as having regular spelling. Another terminology is that of deep and shallow orthographies in which the depth of an orthography is the degree to which it diverges from being truly phonemic. The concept can also be applied to nonalphabetic writing systems like syllabaries.

In an ideal phonemic orthography, there would be a complete one-to-one correspondence (bijection) between the graphemes (letters) and the phonemes of the language, and each phoneme would invariably be represented by its corresponding grapheme. So the spelling of a word would unambiguously and transparently indicate its pronunciation, and conversely, a speaker knowing the pronunciation of a word would be able to infer its spelling without any doubt. That ideal situation is rare but exists in a few languages.

...
Wikipedia