Je voudrais essayer cette robe dans une taille plus grande.

Pronunciation: Zhuh voo-dreh eh-say-yay set rohb dahn oon tye-yuh pluh grahn-duh.

Meaning: I would like to try on this dress in a larger size.

This polite request is essential when shopping for clothing in French-speaking countries, where fitting rooms (cabines d'essayage) are standard in most boutiques.