-able or -ible? English Spelling Rule Test (B2)

English has two suffixes that sound identical — -able and -ible — but are spelled differently, and there is no perfect rule for choosing between them. A few patterns help, though:

• -able is the more common ending by far, and usually attaches to full English words: accept → acceptable, comfort → comfortable, rely → reliable.
• -ible usually appears on Latin-derived stems that can’t stand alone as English words: vis- → visible, poss- → possible, terr- → terrible.
• Words ending in a soft c or g keep the silent e before -able to protect the sound: noticeable, manageable.

The real difficulty is the exceptions. Irresistible ends in -ible even though resist is a perfectly good English word. Indispensable ends in -able even though it feels like it should be -ible. These are the kinds of traps where even confident B2 writers lose marks.

This collection drills 24 words covering the straightforward cases (available, possible, flexible, sustainable) and the classic traps. Each comes with a clear B2 definition and a natural example sentence.

For another suffix pattern challenge, try our -tion vs -sion spelling practice. Otherwise, press play below and decide: -able or -ible?