How should I learn Farsi as a heritage speaker when I find it hard to speak but understand most of it?

Studies of heritage speakers across several languages (including a study of Labrador Inuttitut) describe a specific group called 'receptive bilinguals' — people who understand a great deal but produce little or no speech — and show that these speakers still hold real grammatical knowledge, just less accessible for output than for understanding.^2,9

A study comparing thirty Persian-English heritage speakers in New Zealand to matched monolingual Persian speakers in Iran found the heritage speakers had smaller vocabularies and less varied, less sophisticated word choice in their spoken narratives, though the heritage speakers were far from having no ability in Persian.^1,3,6,7

Among Persian heritage speakers, how old someone was when they moved away from a Persian-speaking environment (or how much sustained childhood exposure they had) predicted vocabulary and fluency better than how positively their family felt about keeping up Persian. Speakers who had more Persian-only childhood exposure, and later exposure to the English-dominant environment, tended to retain stronger Persian skills.^1,6,7

Research on Iranian immigrant families found that parents were often satisfied once their children could hold a conversation in Persian, and rarely pushed for reading and writing skills — partly because of a lack of Persian community schools. This means many heritage speakers' gap isn't really 'speaking vs understanding' but literacy skills never being built at all.^1,3,13

A study of Persian heritage speakers in the US found their spoken and written Persian follows consistent, predictable patterns (in plural forms, compound-verb usage, and subject-verb agreement) that sometimes differ from standard monolingual Persian but are not random errors — the heritage speakers had internally consistent grammar, including innovations not found in either monolingual Persian or English.⁴

A comprehensive handbook on second-language and heritage teaching of Persian devotes dedicated chapters to teaching speaking, listening, reading, and writing to Persian learners, and specifically distinguishes 'linguistic competence of Persian heritage vs second language speakers,' indicating that Persian-specific teaching methods (not generic language-learning advice) do exist and treat heritage learners as a different case from adult beginners.⁵

A survey of over 160 university students of Persian in the US found that many students, especially those with heritage backgrounds, favored 'compensation' strategies (working around gaps in knowledge, e.g. guessing or paraphrasing) and 'social' strategies (interacting with others) over strategies like flashcard-style memorization.⁸

Findings from heritage speakers of Russian, Spanish, Arabic, Korean, and Chinese show a recurring theme: production skills (speaking, complex grammar output) lag behind comprehension, and the size of that gap depends heavily on how much a person used the heritage language actively as a child, not on innate aptitude.^{10,11,12,14,15}

Is it normal for a heritage speaker's Persian to sound different from standard Persian taught in textbooks?

Yes. Research on Persian heritage speakers in the US found that their speech and writing follow consistent internal patterns — in plural forms, in constructions built from a noun plus a light verb, and in subject-verb agreement — that sometimes diverge from standard monolingual Persian, but are systematic rather than careless mistakes. Some researchers argue heritage Persian should be seen as its own legitimate variety of the language rather than a deficient version of it.