Questions & Answers about Wir brauchen einen Experten.
Why does Experten have an -n at the end if we only need one expert?
It looks like a plural, but it is actually singular here! Experte belongs to a special group of masculine nouns called "weak nouns" (or n-declension). When a weak noun is used as a direct or indirect object (instead of the subject), it gets an extra -n or -en added to the end.
Why do we use einen instead of ein?
The verb brauchen (to need) requires a direct object, which means we must use the accusative case. Because Experte is a masculine noun, the indefinite article ein changes to its masculine accusative form, einen.
How do I know that Experte is one of those "weak nouns" that needs an extra -n?
A very helpful rule of thumb: most masculine nouns that represent people or animals and end in -e in their basic form are weak nouns. Examples include der Experte (the expert), der Junge (the boy), and der Kollege (the colleague). They all get that extra -n when they aren't the subject.
If the singular object is einen Experten, how would I say "We need experts" in the plural?