The languages of Scotland belong predominantly to the Germanic and Celtic language families. The main language now spoken in Scotland is English, while Scots and Scottish Gaelic are minority languages. The dialect of English spoken in Scotland is referred to as Scottish English.

The Celtic languages of Scotland can be divided into two groups: Goidelic (or Gaelic) and Brittonic (or Brythonic). Pictish is usually seen as a Brittonic language but this is not universally accepted. They are known collectively as the Insular Celtic languages.

The Goidelic language currently spoken in Scotland is Scottish Gaelic. It is widely spoken in the Outer Hebrides, and also in parts of the Inner Hebrides and Scottish Highlands, and by some people in other areas of Scotland. It was formerly spoken over a far wider area than today, even in the recent past, as evidenced by placenames. Galwegian Gaelic is the extinct dialect of Scottish Gaelic formerly spoken in southwest Scotland. It was spoken by the independent kings of Galloway in their time, and by the people of Galloway and Carrick until the early modern period. It was also once spoken, but much less so in Annandale and Strathnith.

Scottish Gaelic, along with modern Manx and Irish, is descended from Middle Irish, a derivative of Old Irish, which is descended in turn from Primitive Irish, the oldest known form of the Goidelic languages. Primitive Irish is known only from fragments, mostly personal names, inscribed on stone in the Ogham alphabet in Ireland and western Britain up to about the 6th century AD.

Goidelic languages were once the most prominent by far among the Scottish population, but are now mainly restricted to the West. The Beurla-reagaird is a Gaelic-based cant of the Scottish travelling community related to the Shelta of Ireland.

The majority of the vocabulary of modern Scottish Gaelic is native Celtic. There are a large number of borrowings from Latin, (muinntir, Didòmhnaich), ancient Greek, especially in the religious domain (eaglais, Bìoball from ἐκκλησία ekklesia and βίβλος biblos), Norse (eilean, sgeir), Hebrew (Sàbaid, Aba), French (seòmar) and Scots (aidh, bramar).

In common with other Indo-European languages, the neologisms which are coined for modern concepts are typically based on Greek or Latin, although written in Gaelic orthography; "television", for instance, becomes telebhisean and "computer" becomes coimpiùtar. Although native speakers frequently use an English word for which there is a perfectly good Gaelic equivalent, they will, without thinking, simply adopt the English word and use it, applying the rules of Gaelic grammar, as the situation requires. With verbs, for instance, they will simply add the verbal suffix (-eadh, or, in Lewis, -igeadh, as in, "Tha mi a' watcheadh (Lewis, "watchigeadh") an telly" (I am watching the television), rather than "Tha mi a' coimhead air an telebhisean". This tendency was remarked upon by the minister who compiled the account covering the parish of Stornoway in the New Statistical Account of Scotland, published over 170 years ago. It has even gone so far as the verb Backdatigeadh. However, as Gaelic medium education grows in popularity, a newer generation of literate Gaels is becoming more familiar with modern Gaelic vocabulary.

The influence of Scottish Gaelic can be seen particularly in surnames (notably Mac- names, where the mac means "Son of...") and toponymy. The surname influence is not restricted to Mac- names: several colours give rise to common Scottish surnames: bàn (Bain – white), ruadh (Roy – red), dubh (Dow – black), donn (Dunn – brown), buidhe (Bowie – yellow), and Gille- (meaning lad or servant) gives rise to names such as Gilmour and Gillies. Common place name elements from Gaelic in Scotland include baile (Bal-, a town) e.g. Balerno, cille (Kil-, an old church) e.g. Kilmarnock, inbhir (Inver-, Inner-, meaning a confluence) e.g. Inverness, Innerleithen, ceann (Kin-, meaning a head or top of something) e.g. Kintyre, Kinross, and dun (meaning a fort) e.g. Dundee and Dunfermline.