-겠 (Intention & Guess)

The suffix 겠 is one of the most distinctively Korean grammatical markers, and it expresses two related but separate concepts that English speakers often conflate or miss entirely: willingness/intention (what you decide to do) and speculation/prediction (what you guess will happen).

The key insight is that Korean treats these as the same grammatical form because they both express the speaker's subjective commitment or judgment about the future—not objective fact. In English, we use completely different structures: "I will" (neutral future), "I intend to" (intention), "I think it will" (speculation). Korean sees the commonality: all three involve the speaker's mind making a claim about something not yet certain.

When you say 내가 하겠어요 (I will do it), you're saying "I am committing myself to this action." When you say 내일 비가 오겠어요 (I think it will rain tomorrow), you're saying "Based on what I see/know, I'm judging/predicting it will rain." Both are acts of personal assertion about the future, not descriptions of objective reality. This is why the form is the same: you're inserting your will, intention, or judgment into an uncertain future.

This differs radically from English thinking, where future tense (will) is neutral, and you need separate modal structures for intention (going to, intend to) or speculation (will probably, I think... will). English treats the future as a simple temporal shift. Korean treats it as a subjective positioning—you're declaring what you'll do or what you believe will happen. The boundary between "I want to do X" and "I think X will happen" is much softer in Korean because both involve your personal commitment or judgment.