A lot of people are able to read their target language but not speak it. If that happens to someone you know, I wrote a little guide to help diagnose what’s wrong: https://languagecrush.com/forum/t/3425
This is a good topic: My father (who died in 2019 age 83) was such a case! He loved his 3 school languages (French, Latin and English), but later in his life he never spoke them. (Only back then when our family lived in the United States). My father was an avid reader of books in German and English, he knew quite some idoms in Latin and also read poems in French. And he used to compete against me in multilingual Scrabble games (and won 2/3 of them!).