revolution
The German word 'Revolution' is a direct cognate of the English word 'revolution'. It refers to a significant, often sudden, change in a society, political system, or technology. The term is used in various contexts, such as political revolutions (e.g., the French Revolution), industrial revolutions (e.g., the Industrial Revolution), and even scientific revolutions (e.g., the Copernican Revolution).
The revolution has begun
This is a simple present perfect sentence, indicative of an action that has begun in the past but is still ongoing now, hence the usage of 'has begun' in the translation.
Revolution is necessary
This German phrase follows regular subject-verb-object order in its sentence structure. 'Ist' is the third person singular present of 'sein' (to be), used here to indicate necessity.
He is talking about revolution
This phrase is an example of using the verb 'sprechen' (to speak) with the preposition 'über' (about) to indicate the topic of conversation. The subject 'Er' translates to 'he' in English.