Linguistics is the scientific study of natural language. Linguistics encompasses a number of sub-fields. An important topical division is between the study of language structure (grammar) and the study of meaning (semantics and pragmatics). Grammar encompasses morphology (the formation and composition of words), syntax (the rules that determine how words combine into phrases and sentences) and phonology (the study of sound systems and abstract sound units). Phonetics is a related branch of linguistics concerned with the actual properties of speech sounds (phones), non-speech sounds, and how they are produced and perceived.
Other sub-disciplines of linguistics include the following: evolutionary linguistics, which considers the origins of language; historical linguistics, which explores language change; sociolinguistics, which looks at the relation between linguistic variation and social structures; psycholinguistics, which explores the representation and functioning of language in the mind; neurolinguistics, which looks at the representation of language in the brain; language acquisition, which considers how children acquire their first language and how children and adults acquire and learn their second and subsequent languages; and discourse analysis, which is concerned with the structure of texts and conversations, and pragmatics with how meaning is transmitted based on a combination of linguistic competence, non-linguistic knowledge, and the context of the speech act.
Linguistics is narrowly defined as the scientific approach to the study of language, but language can be approached from a variety of directions, and a number of other intellectual disciplines are relevant to it and influence its study. Semiotics, for example, is a related field concerned with the general study of signs and symbols both in language and outside of it. Literary theorists study the use of language in artistic literature. Linguistics additionally draws on work from such diverse fields as psychology, speech-language pathology, informatics, computer science, philosophy, biology, human anatomy, neuroscience, sociology, anthropology, and acoustics.
Within the field, linguist is used to describe someone who either studies the field or uses linguistic methodologies to study groups of languages or particular languages. Outside the field, this term is commonly used to refer to people who speak many languages fluently.
Unless you wnated to know why "marsquake" wouldn't work.