さあ

さあ is a common interjection with two distinct uses depending on intonation and context.

SENSE 1 — ENCOURAGEMENT/INITIATIVE:

Used with a rising or energetic tone to prompt action or signal the start of something.

• さあ、始(はじ)めよう！: Come on, let's start!
• さあ、行(い)くよ！: All right, let's go!
• さあ、食(た)べよう: Now then, let's eat

SENSE 2 — UNCERTAINTY/EVASION:

Used with a drawn-out or falling tone (さあ...) to express that you don't know or are unsure. Often used as a soft way to avoid answering directly.

• 「いつ届(とど)く？」「さあ...」: "When will it arrive?" "Hmm, I'm not sure..."
• さあ、どうでしょうね: Well, I wonder about that

SIMILAR WORDS:

• じゃあ: well then (transitional, moves to a new topic or action)
• では: well then (more formal version of じゃあ)
• ええと: um, let me see (hesitation while thinking)

PRONUNCIATION:
The vowel is typically lengthened. The intonation distinguishes the two senses: energetic for encouragement, trailing off for uncertainty.