Sarah H. answered 08/25/24
It really depends. Do you want to focus on being able to speak a language (vocabulary) or do you want to know how to write sentences (grammar)?
If you are a complete beginner at learning a language, then I would say that focusing on vocabulary first is important because you want to get the basics down and be able to hold a conversation. If you don't want to learn how to write in a language, then you can just focus on vocabulary and not worry about grammar. A lot of people are able to speak their native language fluently without knowing the grammar rules.
However, if you really want to immerse yourself in learning a new language, then it's important to focus on both grammar and vocabulary. Me personally, when I learn a language, I do my best to focus on both grammar and vocabulary. But if I find the grammar rules to be too difficult, then I focus on vocabulary first. Personally, when I teach French to other people, I focus on both vocabulary and grammar because in French language, grammar is very important as French grammar is very different from English grammar (ex: French words need to have a definite/indefinite article always unlike English language)
To learn a new language, is it required to learn its grammar rules first? No. But, it depends on you as a learner what you want to focus on. I would say if you are just beginning to learn a language, focus on vocabulary and being able to hold basic conversations first before you start with grammar.