[livealife]

This is because in English it's not always that you speak what you write. Pronunciation is different for the same letter in different cases. In some languages (mainly Indian) like Hindi, we speak what we write and we write what we speak i.e. Our letters have a definite and unique sounds.

[AmIDev]

While this is true, the pronunciations are not consistent across languages that use Devanagari script. ज्ञ is pronounced like "gy" in Hindi, but "ny" in Marathi. ज is pronounced like "jy"(with the य sound) in Hindi-ish languages, but without य in Marathi. Some sounds are completely missing/unused is some languages, like ळ and ण.

So non-native speakers with another Devanagari language as mothertongue still get pronunciations wrong.

[gholap]

Also, even within Marathi, at least for the letters ज and च, how you pronounce them depends on the word. You have to know the correct pronunciation beforehand, as it can't really be guessed from the word.

जेजुरी is my favourite example. चिंच is a close second :)

[magnio]

That property is called phonemic orthography, and some examples include Finnish, Turkish and Esperanto.