Questions about dictionary lookup techniques and associated functions to correctly spell, use, categorize and translate words from many different languages as well as study their etymologies.
For most users, the first introduction to this facility is the DictionaryLookup command that takes in a StringExpression pattern and returns matching words from the default dictionary. Dictionaries are available in multiple languages and can be specified as an option to the command. Word inclusion is checked with a DictionaryWordQ predicate.
The goal of functions associated with words and their usage is to primarily analyze text documents in order to extract information. In this regard, WordFrequencyData can provide historical information about a word usage from a corpus of published texts.
Also included in the Wolfram Knowledgebase are the curated dictionaries as well as LanguageData from multiple important languages . WordTranslate can help with word translations between available languages. The extended TextTranslate can translate documents between available languages.