Lexical change is also part of language changes. There are two interesting topics in lexical change: those are borrowing or copying; cultural and core vocabulary.
First, copying or borrowing is an innovation in the lexicon change. Copying means that a word is copying or borrowing from one language to other language. For example, when Indonesia was colonized by Dutch, some words in Indonesian are influenced by it. The word ‘zuster’ in Dutch become ‘suster’ in Indonesia. In Bataknese, there are also some words that influenced by Dutch like ‘cigarette’ in Dutch become ‘sigaret’ in Bataknese and the word ‘vacancy’ in Dutch become ‘pakansi’ in Bataknese.
Second, cultural or core vocabulary. Core vocabulary is basically vocabulary that we can expect to find in all human languages. I think it’s like the original vocabulary of one language. It is the words to express meaning like ‘eat’, ‘sad’, ‘laugh’, etc. Cultural vocabulary refers to meanings that are culture-specific, or which people learn through the experience of their own culture. I think it’s like one culture vocabulary that cannot find in other culture; for example, the system of clans in Bataknese, the tradition of Thanks Giving and Halloween in America, etc.
To sum up, lexical change is a process of words change. It can be influenced from outside or inside. Outside means it’s influenced by other language or culture while inside means it’s influenced by the language or culture itself.
Crowley, Terry. 1997. An Introduction to Historical Linguistics. Oxford University Press: Australia.