Sorry for double posting.
Besides Sound Changes, Grammatical changes and Semantic changes are also important aspects of language evolution.
It is said that languages have the following pattern of morphological changes:
analytical > agglutinating > fusional > analytical
a way to gain new affixes is grammaticalization. Generally, grammaticalization has the following pattern:
content words(nouns, words, etc.) > functional words(adpositions, particles, etc.) > affixes
you can see here for some common patterns of grammaticalization: https://books.google.com.tw/books?id=rP ... on&f=false
In my opinion, sound changes described above may cause morphological changes(for example, if you originally had nominal cases solely distincted by means of final vowels, and now original final vowels are all reduced to /ə/ or have become lost, how come can you still have nominal cases?); also, regularization can also cause morphological changes, irregular forms tend to decrease from time to time, but irregular forms that are used very often are resistant to regularization.
Besides, there's a specific way for negations to evolve, it is called the Jespersen's Cycle, the Jespersen's Cycle is listed below( https://en.wikipedia.org/wiki/Jespersen%27s_Cycle
), it seems to be connected to both of the morphological and syntactic aspects of the grammar of a language:
preverbal negation > double negation with both preverbal negation and postverbal negation > postverbal negation
Syntactically, word orders can occasionally change, especially when language contacts happen. Besides mutual borrowing, language contacts can also make aspects of the grammatical structures, and the phonological systems, of languages more similar, that is, languages of communities that have many interactions tend to become more similar in respect of grammar(both of morphology and syntax) and phonology.
Semantically, even if there are no loanwords, some words can become obsolete and be replaced by other words from time to time and from place to place, so after a certain period of time, different dialects can use different words for the same meaning; also, the meaning of a word can also change from time to time.
The meaning of a word may not shift completely first, sometimes the range of meanings just extend or shrink; also, metaphorical meanings of a word is still a part of the meanings of the word, they must also be considered, metaphorical meanings of a word can also be used in compounds as their literal meanings. Without the use of metaphors, it can sometimes become increasingly hard to describe some phenomena.
Metaphorical use of words exist in all languages without a single exception, and there are some patterns of metaphors that are common to most if not all languages. For example(taken from http://www.unepd.info/IntlYearofLanguages.html
), all languages have metaphors that:
- Show “time” in terms of movement through space (along a “time line” with “distant” dates “far” in the future” or “nearby” dates “coming up soon”.(different languages can do this very differently, but it is the matter of how they do it, not the matter of whether they do it at all)
- Show importance in terms of size: all languages describe “important events” as “big” (i.e., “it’s a “big day for our team”, less important ones as “small” (e.g., “it’s just a small, unimportant detail”)
- Show positive emotions in terms of “brightness” or “higher temperature” (“Her smile “lights up” the room”, “He is a very warm person”), less positive ones in terms of “dullness” or “coldness” (“After she left, his world went gray”, “He can be as cold as a fish”)(however, it seems that "hotness" is connected to "anger" a lot)
- Show difficulty or ease in terms of “hardness” or “softness”, “bitterness” or “sweetness” (“go through a hard time”, “have a soft job”, “have a bitter experience”, and “know sweet success”)
(Above information on “metaphor” is from a presentation by Prof Carmen Betones, University of Almeria, curso de verano 2008, Fine Art, Language, and Synesthesia)
Besides, it seems that showing relative directions
in terms of body parts is also very common in many languages.
It seems that if an originally honorific word is used too often, it can become neutral and even somewhat derogative; also, some words that are originally derogative can become less derogative after a certain period of time.
As far as I can see, words related to certain areas are more prone to gain derogative meanings, like words related to sex, excrements and intelligent disabilities(idiot and retardation were originally medical words, but now they have become offensive words).
Some cultures have taboos related to words that have become the names of the dead people and other occasions, and it seems this habit also serves as a device of semantic changes, you can read the following articles:
you can go to http://semshifts.iling-ran.ru
to know how the meanings of a word may change.
For loanwords, functional words and grammatical affixes are very resisting to borrowings, that is, they are very unlikely to be loanwords(although the English 3rd plural forms are of Norse origin); common, everyday words(you can google the Swadesh list
and the Lepizig-Jakarta list for some likely examples of such words, another way to know likely examples is to look for English words that are inherited from Old English) like those related to core kinships(father, mother, brother, sister, etc), body parts, natural phenomena and basic verbs are also pretty resisting to borrowings; also, in my opinion, verbs might be more resisting to borrowings compared to nouns.