das Deutsch
German
The German language.
Sein Deutsch hat sich in den letzten Monaten stark verbessert.
His German has improved a lot in the last few months.

German
Loading your saved state.
German
The German language.
Sein Deutsch hat sich in den letzten Monaten stark verbessert.
His German has improved a lot in the last few months.

'Das Deutsch' (German) is a noun formed from the adjective 'deutsch' (German). This process is called nominalization and is common with languages.
Für viele ist das Deutsch eine schwere Sprache.
For many people, German is a difficult language.
When talking about the language in general, especially with verbs like 'lernen' (to learn), 'sprechen' (to speak), or 'verstehen' (to understand), 'Deutsch' (German) is usually used without an article.
Sprechen Sie Deutsch?
Do you speak German?
When 'Deutsch' (German) refers to the school subject, it is almost always used with the preposition 'in'. You have a grade 'in Deutsch' (in German) or write an exam 'in Deutsch' (in German).
In Deutsch lesen wir gerade einen Roman von Kafka.
In German, we are currently reading a novel by Kafka.
German studies
'das Deutsch' and 'die Germanistik' both deal with the German language. 'Deutsch' means either the language itself or the school subject. 'Germanistik' means an academic field, usually at university, in which the German language and German-language literature are studied in more detail. Learners may confuse the words because both occur in the area of language and literature. For everyday life, school, and language learning, you usually say 'Deutsch'. For university study or research, you say 'Germanistik'.

Vor dem Termin übt er zur Sicherheit noch etwas Deutsch.
Before the appointment, he practices a little more German just to be safe.
Für die Bewerbung beschreibt sie, warum sie Germanistik studieren möchte.
For the application, she describes why she would like to study German studies.