だと / たら / なら — three conditionals (Cure Dolly)

The trio

	form	core	Y-clause may be
だと	noun + だ + と	natural/automatic consequence — “when X, then Y follows”	non-volitional (自動的な帰結): 恥ずかしい, 大丈夫, 太る
たら	verb/adj/noun + たら	one condition met → then	anything, incl. requests
なら	noun/plain + なら	premise-taking — “if/as it’s X, then…”	volitional OK: requests, advice, decisions

だと (だ + と)

人間が相手だと「間違えたら恥ずかしい」と思う = if the partner’s a human, you (naturally) think “I’d be embarrassed if I mess up”
雨だと中止だ = if it rains, it’s cancelled (deduction)
✗ 行くと気をつけて — と can’t lead into a request/advice
だ + と = copula + quotative-ish と → “supposing it’s X / saying it’s X”

たら

間違えたら恥ずかしい = if you make a mistake, embarrassing
One concrete condition; the most versatile. Past-form + ら = “when/if that state is reached”.
安かったら買う = if it’s cheap, I’ll buy it

なら

相手がAIなら大丈夫 = if it’s an AI, [no matter how much] it’s fine
Takes the other person’s premise / a given situation: “well, if that’s the case…”
行くなら気をつけて ✓ (advice after なら — allowed)
東京に行くなら、この店に行ってみて = if you’re going to Tokyo, try this shop

The three in one sentence

人間が相手だと「間違えたら恥ずかしい」と思うかもしれませんが、相手がAIならいくら間違えても大丈夫です。 “human — is-partner — if, — ‘mistake-make-if — embarrassing’ — think — may — but, — partner — AI — if, — how-much — mistake-make-even — fine — is.”

だと vs なら, head to head

	だと	なら
Feel	deduction / automatic result	provisional premise, “then…”
Volition in Y	✗ (no requests/commands)	✓
Example	雨だと行けない (if rain, can’t go — automatic)	雨なら行かない (as for rain, I won’t go — my decision)
EN gloss	“when/if it’s … that means …”	“if it’s … (as you say), then …”

Siblings elsewhere

と-conditional (dictionary form + と) — see [japanese/to-conditional]
たらいいのに = counterfactual wish — see [japanese/tara-ii-no-ni]
いくら〜ても / どんなに〜ても — concession, see [japanese/ikura-temo]

Source

Ebot lesson 2026-09-05 — 相手がAIなら… sentence; user asked why だと and なら coexist. Cure-Dolly glosses.