Nouns ending in -age are usually masculine.
The suffix often marks an action, a result, or a collection.
Is apprentissage masculine or feminine?
l'apprentissage
The rule behind it
98.8% of -age nouns are masculine
In context
Il se concentra sur l'apprentissage des prépositions.
He concentrated on his study of prepositions.
Tom est obsédé par l'apprentissage du français.
Tom is obsessed with learning French.
La répétition est la mère de l'apprentissage.
Repetition is the father of learning.