Learn Farsi: هر چه رمان‌های بیشتری می‌خوانم، این متن‌ها را روان‌تر ترجمه می‌کنم. - The more novels I read, the more fluently I translate these texts.

The sentence starts with har che (literally "whatever") and a comparative word, bishtari (more). The second half of the sentence uses another comparative, ravan-tar (more fluently). Together, har che ... [comparative] ... [comparative] creates the "the more ... the more ..." meaning.

Why is there an -i suffix at the end of bishtari?

The -i here is the indefinite suffix, meaning "some" or "an amount of". When saying "more novels" in this structure, Farsi builds it as roman-ha-ye bishtari, which translates closely to "some greater number of novels". This is standard when a plural noun phrase with "more" is the object of the first clause.

What does ravan mean, and why doesn't it have an adverb ending?

Ravan means "flowing", "smooth", or "fluent". In Farsi, most adjectives can also be used directly as adverbs to describe an action without adding any special suffix. Adding the comparative -tar makes it ravan-tar, which simply means "more fluently" in this context.

Why do we use the object marker ra after in matn-ha?

Ra is used to mark a specific direct object. Since you are talking about translating "these texts" (made specific by the word in, meaning "these" or "this"), Farsi requires ra right after the noun phrase to show it is the target of the verb.