To mix English into your Nepali text. Simply put any text you want to keep in English inside the curly {} brackets.
Example: yo {mobile} mero ho. = यो mobile मेरो ह
Phonetically similar letters: ta = त, Ta = ट, tha = थ, Tha = ठ, da = द, Da = ड, dha = ध, Dha = ढ, na = न, Na = ण, sha = श, Sha = ष ... The (upper or lower) case doesn't matter for the rest of the letters2