たら

The たら form is one of the most flexible conditional expressions in Japanese. It is formed by adding ら to the past tense (た-form) of verbs, adjectives, and nouns. It can express "if", "when", and "after" depending on context.

Formation

• Verbs: Take the た-form and add ら → 食べた → 食べたら, 行った → 行ったら
• い-adjectives: Replace い with かったら → 安い → 安かったら
• な-adjectives / Nouns: Add だったら → 静か → 静かだったら, 学生 → 学生だったら
• Negative: ない → なかったら → 行かなかったら

Hypothetical condition – "if"

たら is used to express a hypothetical condition: if A happens, then B.

This usage is similar to 〜～ば and 〜～と, but たら is the most flexible and natural-sounding conditional in everyday conversation. Unlike ～と, the result clause can contain requests, suggestions, and volitional expressions.

Temporal condition – "when" / "after"

When the condition is something expected or certain to happen, たら takes on a temporal meaning: when/after A happens, B.

In this usage, A always happens before B – there is a clear sequential relationship between the two events.

Unexpected discovery – "when I did…, I found that…"

When used with a past tense result clause, たら often describes something unexpected that was discovered or happened as a result of the first action.

This is a distinctive use of たら that the other conditionals (～ば, ～と, ～なら) cannot easily replace. Both clauses describe events that actually occurred.

たら vs. other conditionals

• たら is the most flexible and conversational. It works for hypothetical, temporal, and counterfactual conditions.
• ～と implies a natural or automatic consequence and cannot be used with requests or commands in the result clause.
• ～ば focuses on the condition itself and is slightly more formal.
• ～なら is used when responding to information the speaker has just learned ("if that's the case…").

Counterfactual – "if it had been…"

たら can also express counterfactual situations – things that didn't actually happen.