We need to understand that growth within the context of the population growth as a whole. The Inuit population is growing quickly. A lot of that growth is because they have high fertility rates. We see the aboriginal population, as a whole, growing substantially over time. However, not all that growth is necessarily because of high fertility. It's because of people who are newly identifying as indigenous on the census.
Therefore, when you're looking specifically at Inuktitut, I think you could credit the growth of the number of speakers to high fertility. Most Inuit live in Inuit Nunangat, which would be Inuit homeland, where the language is more common and would be easier to maintain. Dene, I believe, would be similar in the sense that the speakers are concentrated in communities where there is a high number of speakers.