I am a foreigner in English language.
Language dictionaries contain translations of words from one language to another. But this does not work very well for the meaning of the words. Each word can have several different meanings in each language. During the translation process this has to be taken into account. Consider the German word "Geist". It translates into the following English meanings:
animus apparition esprit genie ghost intellect mind nous phantom psyche specter spirit wit wraith
If you look up each of those translated words individually you create a snowball of meaning.
die Abneigung die Absicht der Animus die Feindseligkeit der Geist der Groll der Hass die Neigung belebender Geist feindselige Stimmung
die Erscheinung der Geist die Geistererscheinung das Gespenst
...and so on. Then one can translate those words back to English.
animosity animus antipathy averseness aversion deviation disfavor disinclination dislike disrelish idiosyncrasy indisposition objection reluctance repugnance resentment bibliophobia
Look at what happens to the meaning. It is pretty amazing.
animus Feindseligkeit animosity hostility Neigung affection bent bias notion propensity tilt warp apparition der Geist das Gespenst
Finding out about the roots of language.
Etymology is the study of the history of words and how their form and meaning have changed over time.
For languages with a long written history, etymologists make use of texts in these languages, and texts about the languages, to gather knowledge about how words were used at earlier stages, and when they entered the languages in question. Etymologists also apply the methods of comparative linguistics to reconstruct information about languages that are too old for any direct information to be available. By analyzing related languages with a technique known as the comparative method, linguists can make inferences about their shared parent language and its vocabulary. In this way, word roots have been found which can be traced all the way back to the origin of, for instance, the Indo-European language family.