But to do so, more schools need to improve their immersion teaching at all stages - pre-school, primary and secondary - says the report, Gaelic Education: Building on the successes, published this week.
The early stages of Gaelic medium education are defined as "total immersion", where no other language is used, and in examples of best practice, this continues until P3 or P4. The next phase, where the development of English is introduced, is referred to as "immersion"; here, all of the curriculum should continue to be delivered through the medium of Gaelic.
Inspectors found, however, "too great a variation in practice" in schools' interpretations of immersion and total immersion.
"For example, schools move from the total immersion phase at different stages. Where this happens too soon, children are not sufficiently fluent with the phonics and structures of Gaelic before they begin to develop their skills in English language. This can impact adversely on children's progress in Gaelic," says the report.
Some schools referred to the total immersion phase as the "bilingual phase" and allowed English to be too dominant, say the inspectors.
"This results in children not being as fluent as they can be. In weaker practice, some schools think that only certain subjects can be delivered through the medum of Gaelic," they add.
- The provision of written national guidance for Gaelic medium education and Gaelic learning;
- a consistent policy on how to correct children's language errors so they are not allowed to become the norm;
- closer working between primary and secondary teachers to develop young people's specialist vocabulary.