Quick answer: mates’ rates (informal conversational) — A friendly discount given by a tradesperson, freelancer, or shopkeeper because the customer is a friend. Meanwhile, sound (Informal · approving) — Decent, reliable, friendly, or good. As a short reply, “sound” can mean “okay,” “agreed,” or an appreciative acknowledgment.
1. mates’ rates ↗
Category: Across the Atlantic
Register: informal conversational
Regions: UK, IE
A friendly discount given by a tradesperson, freelancer, or shopkeeper because the customer is a friend.
When it fits: Use “mates’ rates” in casual conversation, messaging, or sociolinguistic discussion when the listener shares the register and context makes the tone unmistakable.
When to avoid: Avoid relying on “mates’ rates” in formal academic, legal, clinical, or HR correspondence where unambiguous plain English prevents misinterpretation.
“Everyone in the group chat recognized “mates’ rates” immediately, even though we had to rephrase it in plain English for the project summary.”
In plain English: Everyone in the chat understood the informal expression (a friendly discount given by a tradesperson, freelancer, or shopkeeper because the customer is a friend.), though we used standard wording in the formal report.
2. sound ↗
Category: Across the Atlantic
Register: Informal · approving
Regions: UK, IE
Decent, reliable, friendly, or good. As a short reply, “sound” can mean “okay,” “agreed,” or an appreciative acknowledgment.
When it fits: Use it for informal approval or a friendly response where the regional sense fits. Specific behavior makes a compliment more meaningful.
When to avoid: Avoid translating every sound as noise. In formal reasoning, a sound argument is well-founded or valid in a technical sense, not simply a friendly person.
“She waited with me until the bus came. She is sound.”
In plain English: She is considerate and decent.
Test both expressions in context
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