Each Other — Mutual and Reciprocal Actions

Practice 'each other' for reciprocal actions (A acts on B and B acts on A) and distinguish it from reflexive pronouns (themselves, ourselves). Covers 'each other's' possessive form.

Each Other: Expressing Mutual and Reciprocal Actions

Each other is a reciprocal pronoun expressing that two (or more) people perform the same action on one another simultaneously: Tom helps Lisa and Lisa helps Tom. It differs from reflexive pronouns (themselves, ourselves), which mean each person performs the action on themselves. Research on learner English shows that reflexive-for-reciprocal substitution — 'They looked at themselves' meaning they looked at each other — is a common B1 error, particularly for speakers whose L1 uses a single form for both reflexive and reciprocal. A second frequent error is the non-existent form 'each others' (plural): 'each other' is invariable and never takes -s, though the possessive is 'each other's' (apostrophe before the s).

Each Other — Mutual Action

Tom and Lisa help each other with homework. (A helps B; B helps A)
We haven't seen each other since the wedding.
My parents call each other every day when they're apart.

Each Other's — Possessive

The twins always finish each other's sentences. (apostrophe before -s)
They borrowed each other's notes before the exam.

Each Other vs Themselves/Ourselves

They looked at each other. (A looked at B; B looked at A — mutual)
They looked at themselves. (each person looked in a mirror — reflexive)

Common Mistakes

✗ Tom and Sara congratulated themselves after winning. → ✓ each other. (they congratulated one another)
✗ We email one other every week. → ✓ each other. ('one other' is not a valid form)
✗ The teachers supported each others during the difficult period. → ✓ each other. (no plural -s on 'each other')