CRFL, often augmented to CaReFuL, is a memory aid for English-speaking students of French as a foreign language. Students use it to remind themselves of which final consonants (aka terminal consonants or word-ending consonants) are usual exceptions to the general rule that in French pronunciation, final consonants are usually silent.

Final K is, in fact, normally pronounced as well, but has probably been ignored because the letter is rare in French, generally appearing only in borrowed or learned words. In borrowed words, final consonants often retain their pronunciation because the borrowing occurred after the transformation that led to the dropping of final consonants in native words.

For example

In the following French words, the final consonants are silent:

• coup
• devant
• maintenant
• part
• prix
• restaurant
• salut

However, in the words below, the final consonants are heard:

Exceptions

Infinitives ending in -er and words ending in -ier

The main exceptions to the CaReFuL rule are:

1. It does not apply to infinitives ending in -er, which end in an /é/ sound. For example: parler (/par·lé/); manger (/man·gé/).
2. It does not apply to words ending in -ier, which is pronounced as /ié/. For example: panier (/pa·nié/); gibier (/ji·bié/).

Words in which the F is not pronounced

The F is not pronounced in cerf, clef, nerf, in the plurals œufs and bœufs, and in the compound words cerf-volant and chef-d'œuvre.

Words in which final letters other than C, R, F, and L are not silent

Below are examples of words in which a final consonant other than C, R, L, or F is pronounced. Most frequently these words are learned words from Latin and Greek, borrowings from other languages, or onomatopeia. In linguistics and poetry, onomatopoeia is the device of a word, or occasionally, a grouping of words, with a sound imitating the sound it is describing, such as bang, click, fizz, hush or buzz. Onomatopoetic words exist in every language, although they are different in each. ...

Plus

The word plus is pronounced differently based on its meaning and context. An overview of the rules, in French, is on the website of the Ville de Quebec.