You're trying to explain that your husband's sister's husband is visiting next weekend, and somewhere between word three and word seven, English betrays you. Is he a brother-in-law? A cousin-in-law? Just "my husband's sister's husband"? English's in-law system is actually simpler than it looks — once you know the pattern, it covers most situations gracefully.

Quick Answer

Add "-in-law" to the basic relationship word: mother, father, brother, sister, son, daughter → mother-in-law, father-in-law, brother-in-law, sister-in-law, son-in-law, daughter-in-law. The plural goes on the first word: "mothers-in-law," "brothers-in-law." For more distant marriage relatives, English usually says "my husband's cousin" or "my wife's uncle" rather than inventing a label.

What People Actually Say

Common Mistakes

• "My mother in law is here." → "My mother-in-law is here." · Always hyphenated when written.
• "My mother-in-laws called." → "My mother-in-law called." (one person) / "My mothers-in-law called." (two people) · The plural -s goes on "mother," not "law."
• "She is my husband sister." → "She is my husband's sister." or "She is my sister-in-law." · Possessive 's is required.
• "I went to dinner with my in laws." → "I went to dinner with my in-laws." · Hyphenated. The word for "spouse's family as a group."
• "He is my law brother." → "He is my brother-in-law." · The order is fixed: relationship + "-in-law."
• "My step mother-in-law." → "My husband's stepmother." · English doesn't usually stack "step" and "in-law"; rephrase with the possessive.

Mini Dialogues

Dialogue 1 — Weekend plans A: Doing anything fun this weekend? B: My in-laws are coming over. Big dinner. A: How many of them? B: Parents, both brothers-in-law, and one sister-in-law with her two kids. A: That's a lot of cooking. B: My husband's doing the cooking. I'm doing the smiling.

Dialogue 2 — Family chart confusion A: Wait, who's Marcus again? B: My brother-in-law. He's married to my sister. A: Oh — so he's your sister's husband. B: Right, but in English we just say "brother-in-law" for both directions — sibling's spouse or spouse's sibling. A: That's actually convenient. B: Saves a lot of breath.

Tone Notes

"In-laws" can be neutral, warm, or loaded — context tells you which. "I'm so lucky with my in-laws" is genuine; "you know how in-laws are" leans toward shared eye-roll humor. In English-speaking workplaces, mentioning in-laws is normal small talk — "we're spending the holidays with my in-laws" is perfectly safe to say. Avoid criticizing in-laws to people you barely know; it lands worse in English than complaints about your own parents. When introducing them, "This is my mother-in-law, Carol" works for any setting. If you can't remember the exact term in the moment, "my wife's brother" or "my husband's mom" is always understood and always polite.

Practice: Choose the Natural Sentence

1. Introducing your husband's mother at a party:

   • A. "This is my mother in law."
   • B. "This is my mother-in-law."

2. Talking about two of your spouse's brothers:

   • A. "Both my brothers-in-law live nearby."
   • B. "Both my brother-in-laws live nearby."

3. Describing your sister's spouse to a new friend:

   • A. "He's my brother-in-law."
   • B. "He's my sister husband."

Answer Key

1. B — Hyphenated in writing; spoken the same way.
2. A — Plural -s goes on "brothers," not "law."
3. A — "Brother-in-law" covers both sibling's spouse and spouse's sibling; B is missing the possessive 's.

Tiny Summary

Add "-in-law" to the six core family words, always hyphenated, with the plural on the first word. Use "my in-laws" for the group. For more distant marriage relatives, English skips the label and uses a possessive: "my husband's cousin," "my wife's uncle." Simple system, friendly tone, and you're set.