Explaining the differences between linguistics, semantics, etymology and philology in the world of languages.
This is a broad definition for what is generally termed the study of language itself, often called the science of language. The term traces back to the Latin root lingua which meant only the muscle known as the tongue, but also the words that issued forth courtesy of that tongue. Linguistics as practiced in modern times is concerned with studying the structure of language. Therefore, there is comparative linguistics that studies the differences and similarities between various languages in an attempt to unlock commonalities of relationship between them. Then there is structural linguistics which attempts to find a core relationship of similarities that ties all the many different languages together.
Semantics is the branch of linguistics that is concerned with why certain words signify certain things. In other words, what is the entire comprehensive definition of word beyond its denotative one found in a dictionary? Semantics looks to such things as the specific connotation of a word. Take the sentence “The girl was very hot.” By itself the meaning of that sentence would vary from person to person depending upon such things as age, cultural background, etc. By placing the sentence within a context you are considering its semantical meaning. “It was summer. The girl was very hot” is completely different in meaning from “She was wearing a string bikini. The girl was very hot.” Semantics also takes into consideration the historical changes in a word.
Etymology is a branch of language study that is similar to that historical concern of semantics. The study of etymology is concerned with how words evolve over the course of usage through time. However whereas semantics really only concern how the meaning changes, etymology involves both meaning and form. For instance, many words we commonly use today to express something evolved from an archaic word, which is different not only in meaning but in spelling too.
Philology dates back to the earliest instances of linguistics, which focused almost exclusively on the study of classic tests, mainly those of ancient Greece and Rome. The main problem here was that there weren’t too many people left who actually spoke those languages so philology was a science that focused only on the literary meaning. Language studies today, including the modern version of philology, are not limited merely to the meaning of language in literary forms, but consider the meaning in terms of how it used when spoken as well. Today, philology has been broadened to mean the study not just of ancient texts, but ancient languages as a whole.
Of course, it is important to understand that there are often significant specialties and differences between these larger and more generalised categories, especially linguistics. For example, there is an entire field devoted to the study of psycholinguistics that attempts to uncover relationships between the mind and the way language is used in connection with psychology. Structuralism became such a dominant movement within the field of linguistics in the 20th century that it might deserve its own individual field.