Group 1 spelling: -cer / -ger
Summary
Verbs in -cer change c to ç, and verbs in -ger add a silent e, before the vowels a and o so the soft /s/ and /ʒ/ sounds are preserved, while the ordinary -er endings stay unchanged.
Explanation
Verbs ending in -cer and -ger are ordinary group 1 verbs: they take the regular -er endings (-e, -es, -e, -ons, -ez, -ent) and sound completely regular. The only complication is purely orthographic. In French, the letter c is soft (a /s/ sound) before e, i and y but hard (a /k/ sound) before a, o and u; the letter g is soft (a /ʒ/ sound, like the s in measure) before e, i and y but hard (as in gare) before a, o and u. To keep the soft sound everywhere, -cer verbs write ç before a or o, and -ger verbs insert a silent e before a or o.
Concretely, -cer verbs change c to ç whenever the ending begins with a or o: commencer gives nous commençons in the present and je commençais, tu commençais, il commençait, ils commençaient in the imparfait, plus je commençai in the passé simple. The same applies to placer, lancer, avancer, prononcer and menacer. The -ger verbs instead keep the e of the stem before a or o: manger gives nous mangeons, je mangeais … ils mangeaient, je mangeai and the present participle mangeant. So do voyager, nager, ranger, changer, partager and bouger.
The key detail is that the change happens only before a and o, never before e, i or y, where the c and g are already soft. This is why you write je commence, vous mangez and, crucially, nous commencions and nous mangions in the imparfait: the imparfait nous and vous endings start with i, so no ç and no extra e is needed there. The adjustment therefore shows up in a predictable cluster of forms — the nous of the present (commençons, mangeons), the singular and third-person plural of the imparfait, the present participle, and the passé simple — but vanishes everywhere the next vowel is e, i or y.
Two pitfalls are common. The first is forgetting the mark altogether and writing *commencons or *mangons, which would force a hard /k/ or hard /g/ pronunciation that no French speaker uses. The second is over-applying the device before e, i or y: learners sometimes carry the extra e or the cédille into forms like the imparfait nous and vous, producing *nous mangeions or *nous commençions — but the correct forms are nous mangions and nous commencions, because i already softens the consonant.
Rule of thumb: keep the soft sound. Add a cédille (ç) to -cer verbs and an extra e to -ger verbs, but only when the ending starts with a or o; before e, i or y, leave the spelling alone.
Examples
Nous commençons le cours et nous mangeons à midi. — We are starting the class and we eat at noon. (In the nous present the ending starts with o, so -cer takes ç (commençons) and -ger keeps e (mangeons).)
Quand j'étais petit, je voyageais beaucoup. — When I was little, I used to travel a lot. (The imparfait ending -ais begins with a, so voyager keeps the e: voyageais.)
Nous nageons dans le lac en été. — We swim in the lake in summer. (Nager (-ger): the silent e is kept before -ons (nageons).)
Il prononçait mal le mot « écureuil ». — He used to pronounce the word "écureuil" badly. (Prononcer (-cer) in the imparfait: ç before the a of -ait (prononçait).)
Nous partageons le gâteau entre tous les invités. — We are sharing the cake among all the guests. (Partager (-ger) keeps the e before -ons (partageons).)
Common mistakes
Nous mangons à midi et nous commencons le travail.
Nous mangeons à midi et nous commençons le travail.
Verbs in -ger keep a silent e before a or o to preserve the soft "zh" sound (nous mangeons, je mangeais), and verbs in -cer take a cédille ç before a or o to keep the soft "s" sound (nous commençons, je commençais). Without them, the g would sound like in gare and the c like a k. The adjustment appears mainly in the nous present and throughout the imparfait, never before e, i or y.
Prerequisites
Related rules
spelling-changepresent-tenseorthography