Loanwords are a record of who talked to whom

Languages borrow constantly. Every language documented has loanwords, and the pattern of what was borrowed from whom, and when, is one of the better historical records available for periods with few written sources.

What gets borrowed

The general rule is that words arrive with things.

New technology, new foods, new institutions, new concepts. When something is introduced, the word frequently comes with it, and the word then persists as evidence long after the introduction is forgotten.

Which means the domains of borrowing tell you the nature of the contact.

Agricultural and craft vocabulary suggests sustained contact between neighbouring populations with different practices.

Administrative, legal and military vocabulary generally indicates political domination, with the borrowing running from the dominant language into the subordinate one.

Religious vocabulary follows conversion, and it is frequently among the most durable — words for religious concepts often survive from the language of the conversion for a very long time.

Trade goods arrive with the names attached, frequently having passed through several languages en route, each modifying the form.

Maritime vocabulary clusters, because sailors were multilingual and ships were mixed, and several languages have nautical terminology borrowed wholesale from a dominant seafaring language of the period.

The layers

English is a well-documented case with several distinct strata.

An early layer from Latin, arriving through trade and through the church. A layer from Old Norse, from settlement — and this one is unusual in including basic vocabulary and even grammatical items, which indicates a very close and prolonged contact rather than a prestige borrowing.

A very large layer from French after the Norman conquest, concentrated in law, government, cuisine and abstraction, which produced the characteristic English pattern of paired words with a plain and a formal register.

Then a scholarly layer from Latin and Greek in the early modern period, deliberately introduced, and continuing borrowing from everywhere as a consequence of trade and empire.

Each layer can be identified by its sound patterns and by its semantic domain, and the layering constitutes a rough history of who was in charge and what they were doing.

What resists borrowing

Some vocabulary is comparatively stable across contact.

Core body parts, close kinship terms, basic numerals, common verbs, pronouns and grammatical function words are generally more resistant, though none is immune. Historical linguists use this differential stability when comparing languages, since core vocabulary is more likely to reflect inheritance than borrowing.

When these categories are borrowed, it signals unusually intense contact — the kind produced by extensive bilingualism, intermarriage or population mixing rather than by trade.

Calques and hidden borrowing

Not all borrowing is visible.

A calque translates the components of a foreign expression rather than importing it. The result looks native and is structurally borrowed, and these are much harder to detect without knowing the source.

Semantic borrowing extends an existing native word's meaning to match a foreign equivalent, leaving no formal trace at all.

Both mean that the visible loanword count understates the influence of contact considerably.

Purism and its results

Attempts to remove foreign vocabulary from a language have been made in many places, generally in connection with nationalism.

Some have succeeded in establishing native alternatives that speakers actually adopted, particularly where the coinages were transparent and where institutional support was sustained.

Many have not, producing official vocabulary that appears in documents and never in speech.

The reliable pattern is that purism works better for new concepts, where there is no established usage to displace, than for existing borrowed words, where speakers have no reason to change.

Words that went and came back

A pleasing category. A word is borrowed from language A into language B, changes form and meaning, and is then borrowed back into A as a new word.

Several languages have pairs of words that are ultimately the same original item, having taken different routes and arrived looking unrelated. Tracing these produces some of the more entertaining results in etymology.

What this is useful for

For historians, loanword strata provide evidence about contact in periods with no records — the presence of agricultural vocabulary borrowed from a particular source, for instance, can indicate who introduced a crop and roughly when.

For anyone else, it is a reminder that the distinction between native and foreign vocabulary is a matter of how long ago something arrived. Words that feel entirely native in any language were at some point new and probably objected to.

Every language is a record of contact, and the languages that feel most distinctive are frequently the ones that borrowed most.