Recognise-Recognize | Commonly Confused Words

Recognise

/ˈrekəgnaɪz/

To identify someone or something as already known

/ˈrekəɡnaɪz/

To identify someone or something from having encountered them before; to acknowledge the existence or validity of.

Every word she recognized as true."Madame!" exclaimed Raoul, on recognizing the sister-in-law of the king.'Did you think I didn't recognize him?'

Recognize is the preferred spelling in American English.
Recognise is often used in British and other forms of English.
Both words have the same pronunciation and meaning.
The difference is mainly in the spelling based on regional preferences.
When writing, consider your audience and choose the appropriate version for American or British English.