GIVE ANSWERS - Deutsch

Hey Sylvia, allow me to enlighten you. Hope you don't mind me explaining simple grammatical principles.

'deutsch' can be used either as an adjective (words like 'good', 'bad', 'tall') or as a noun (words like 'tree', 'sun', 'sky') but in both sentences provided above, it is a noun. It however keeps varying like an adjective.

An adjective has different endings depending on whether it is masculine/feminine, nominative/accusative/genitive/dative, singular/plural but also whether or not it is preceded by a so-called definite article ('the'), indefinite article ('a' or 'one') or nothing.

'In the first sentence, 'Viele' is like having an indefinite article, 'deutsch' is used in its nominative form, plural, hence the ending of the adjective is -e. By the way, 'Deutsche' should be written with a capital letter (you put it correctly in your 3rd sentence).

In the second instance, 'Deutsch' is preceded by 'die', ie the definite article, it is used in its nominative form, plural, therefore the ending will be -en.

Hope it helps.