
sich aneignen
to acquire
To learn a skill, knowledge, or a particular behavior, usually through one's own effort.
Sie hat sich in kurzer Zeit sehr gute Spanischkenntnisse angeeignet.
She acquired very good Spanish skills in a short time.
to acquire / appropriate
Loading your saved state.

to acquire
To learn a skill, knowledge, or a particular behavior, usually through one's own effort.
Sie hat sich in kurzer Zeit sehr gute Spanischkenntnisse angeeignet.
She acquired very good Spanish skills in a short time.

to appropriate
To take something into one's possession unlawfully; to claim something for oneself without permission.
Der Diktator hat sich das Vermögen des Landes widerrechtlich angeeignet.
The dictator unlawfully appropriated the country's wealth.
'Aneignen' (to acquire / appropriate) is a separable verb. The prefix 'an-' goes at the end in a main clause. In subordinate clauses and in the infinitive with 'zu', the verb stays together.
Er eignet sich schnell neue Fähigkeiten an.
He quickly acquires new skills.
The verb is always reflexive and requires the reflexive pronoun in the dative. What one acquires or appropriates is in the accusative. So the structure is: person (subject) + eignet + sich (dative) + something (accusative) + an.
Ich eigne mir gerade die Grundlagen der Programmierung an.
I am currently acquiring the basics of programming.
The meaning depends on the object. If it is abstract knowledge or skills ('eine Sprache' (a language), 'eine Methode' (a method)), it means 'erlernen' (to learn/acquire). If it is concrete property or rights ('Land' (land), 'Vermögen' (wealth)), it means 'unrechtmäßig nehmen' (to take unlawfully).
Sie hat sich einen neuen Arbeitsstil angeeignet.
She acquired a new working style.
In the meaning 'erlernen' (to learn/acquire), the verb is often combined with abstract nouns. Typical collocations are: 'sich Wissen aneignen' (to acquire knowledge), 'sich Fähigkeiten aneignen' (to acquire skills), 'sich Kenntnisse aneignen' (to acquire knowledge/skills), or 'sich eine Gewohnheit aneignen' (to acquire a habit).
Im Laufe der Jahre hat er sich ein enormes Fachwissen angeeignet.
Over the years, he acquired enormous specialist knowledge.
The meaning 'unrechtmäßig nehmen' (to take unlawfully) is used mainly in a formal, legal, or historical context. In everyday language, you would be more likely to use other verbs.
Historische Texte beschreiben, wie sich der Adel Ländereien aneignete.
Historical texts describe how the nobility appropriated lands.
to take over / take on
When it comes to an observed way of behaving, übernehmen and sich aneignen can both be appropriate. Übernehmen emphasizes that the behavior comes from another person and is now being used oneself. Sich aneignen highlights one’s own learning process and the effort required for it.

Jonas eignet sich die ruhige Gesprächsweise seiner Kollegin durch viel Übung an.
Jonas acquires his colleague’s calm way of speaking through extensive practice.
Jonas übernimmt die ruhige Gesprächsweise seiner Kollegin.
Jonas adopts his colleague’s calm way of speaking.