Most Serbian words are of native Slavic lexical stock, tracing back to the Proto-Slavic language. There are many loanwords from different languages, reflecting cultural interaction throughout history. Notable loanwords were borrowed from Greek, Latin, Italian, Persian, Turkish, Hungarian, Russian, English and German.

It is estimated that there are 900–1,200 Greek,^[1] 88–188 German,^{[2] [3]} and an uncertain high number of Turkish and Persian loanwords^[4] in modern Serbian.

Ancient Greek words in Proto-Slavic are identified through phonetic features, some related to Greek phonetic history, others possibly Scythian-Sarmatian or Gothic mediations.^[5] Ancient Greek, non-mediated words are korablja (ark), koliba (cottage, hut), and supposedly trem (porch); Scythian mediations are luk (onion), haluga (fence), koš (basket), talog (dregs), kurva (whore, slut, skank, hooker); supposedly Gothic mediations are crkva (church) and daska (plank).^[6] There exists loanwords in Proto-Slavic from non-Indo-European languages. Among Uralic and Turkic lexemes, estimated to have been adopted between the 3rd and 7th century, surviving into modern Serbian are čaša (cup, mug, glass), knjiga (book), kovčeg (chest), krčag (pitcher), sablja (sabre).^[7] Adoptions from Avaric in the 6th–7th centuries are the titles ban and župan, and klobuk (a type of hat).^[8] South Slavic was also influenced by Bulgar since their arrival in the eastern Balkans in the 7th century, e.g. beleg (landmark), beočug (shackle), bubreg (kidney), pašenog (co-brother-in-law), tojaga (bludgeon).^[9]

The South Slavic languages were greatly influenced by Greek beginning in the Early Middle Ages, through translation of Byzantine works, leaving religious, philosophical and psychological terms.^[10] Late medieval speech had very few loanwords, rather replacing Greek words with calques for linguistical purity.^[10] German linguist Vasmer (1944) recorded 1,000 Greek words in Serbian, most of which were addressed in the Old Serbian form.^[11] Today, it is estimated that 900–1,200 Grecisms (grecizmi) exist in Serbian, more than 400 being in the church-religious section.^[1] In the economical section, apart from Greek, many words in Old Serbian were Romance.^[10] In mining, the majority of words were Germanic, arriving with Saxons.^[10]

The Ottoman conquest began a linguistical contact between Ottoman Turkish and South Slavic; Ottoman Turkish influence grew stronger after the 15th century.^[4] Besides Turkish loanwords, also many Arabic (such as alat, "tool", sat, "hour, clock") and Persian (čarape, "socks", šećer, "sugar") words entered via Turkish, called "Orientalisms" (orijentalizmi).^[4] Also, many Greek words entered via Turkish.^[4] Words for hitherto unknown sciences, businesses, industries, technologies and professions were brought by the Ottoman Empire.^[4] Christian villagers brought urban vocabulary from their travels to Islamic culture cities.^[12] Many Turkish loanwords are no longer considered loanwords.^[13]

In the 19th and early 20th century Serbian, unlike the Croatian, version of the Serbo-Croat language continuum was much more open to internationalisms (words from Latin and Classical Greek) used in sciences and arts (cf. Serbian istorija vs. Croatian povijest = history and such).

English influence is seen in recent times, with the common suffixes -er and -ing.^[14] Examples are kasting, ketering, konsalting, listing, džoging, šoping, etc.^[15] Foreign loanwords are becoming more frequent in sports terminology.^[16]

The differences between Serbian and Croatian is mainly reflected in loanwords.^[17] Bosnian has the most Ottoman Turkish loanwords of all Serbo-Croatian variants.^[4]

Serbo-Croatian vocabulary is of mixed origin, with words borrowed from Greek, Latin, Italian, Turkish, Hungarian, and more recently Russian, Czech and German. Most loanwords have entered Serbian without resistance, while on the other hand in Croatian, linguistic purism was adopted as a policy during Austria-Hungary (against presumed Germanization) and later in Yugoslavia (against presumed Serbian domination). In Croatia, the term "Serbisms" is used for characteristically Serbian words,^[18] unwanted during World War II and the Yugoslav wars, many of which have been replaced by neologisms.^[19]

• Arabic-Persian-Greek-Serbian Conversation Textbook

• Biljana Mišić Ilić; Vesna Lopičić (12 October 2010). Identity Issues: Literary and Linguistic Landscapes. Cambridge Scholars Publishing. ISBN 978-1-4438-2595-5.