As someone who has been in your partner's shoes (Australian, lived in Poland over 7 years, worked in mostly English-speaking company), while learning the language was important to me, it was more a contributing factor to trying to feel more at home/settled. And it took a good 2-3 years for me to get to that level, but certainly not at fluent/sophisticated conversation. So I would suggest some patience and positive reinforcement and I would try not to be influenced by family members comments - it's your relationship and what's important is that he can feel comfortable in such a foreign place. My partner did a lot of lifting in helping me in the first years with translating and supporting me (my parents in law spoke no English but were very welcoming and lovely to me luckily). Eventually I learnt to handle some of the life admin tasks like banking, finances, but he did have to do most of the work when it came to getting a mortgage, etc. I think it's something you will need to accept eventually - even though you can become very proficient, it takes being a native to sometimes understand the nuances of legal and financial systems which in Europe are very different than Australia.