Understanding with 分かります
Open chapter 1 and first use the word support directly below. Then read the understanding example aloud and point to the understood content and が.
1. What you understand takes が
With 分かります, が marks the content that is understood by the speaker: 日本語が分かります. Translate the whole pattern naturally as ‘I understand Japanese’.
Ask about that content with 何が分かりますか or use a specific topic. Do not simply treat 分かります as an ordinary を verb.
日本語が分かります。
何が分かりますか。
2. Understanding or not understanding
The positive polite form is 分かります; the negative is 分かりません. The particle が does not change: 漢字が分かりません.
A yes-no question ends in か. Answer according to your chosen situation and repeat the content if that helps clarity.
漢字が分かりますか。
いいえ、漢字が分かりません。
3. Understanding is not the same as studying
日本語が分かります describes a state or ability: Japanese is understood. 日本語を勉強します describes an activity: you spend time studying Japanese.
Therefore choose both the right verb and its particle. Someone can say 日本語を勉強します and still say 日本語が分かりません.
4. Build a language profile
Choose three languages or writing systems. Write what you understand for one, what you do not yet understand, and what you study for a third. The statements may be fictional.
Check each pair: が goes with 分かります or 分かりません; を goes with 勉強します. Let the meaning determine the pattern.