Problem is, this isn't about learning a language. Language requirements before permanent residency or citizenship is one thing. This is already a requirement in the UK as well as other countries. Requiring it before a spouse enters the country is another. This is definitely going to complicate things for certain families. Mostly poor people from certain places.
It's totally uncalled for. There is no work requirement for a spouse visa if the family can support themselves without public funds, so saying it will lead to work is BS. As I said, this is aimed at a certain type of immigrant. This will probably just be another cost to the already costly process for those from English speaking countries, those with strong educational systems, or those from families that could afford better education.
For instance, my future sister-in-law may or may not speak English well enough, but my brother-in-law speaks Ukrainian well enough that during his visits there, her not speaking English well enough doesn't really mean their relationship isn't valid. This new rule may delay or prevent their plans to marry here in the UK in the autumn. I keep trying to convince him to go the EEA route in another country anyway. It's a lot cheaper and causes fewer headaches.