Most of the Portuguese vocabulary comes from Latin because Portuguese is a Romance language.
However, other languages that came into contact with it have also left their mark. In the thirteenth century, the lexicon of Portuguese had about 80% words of Latin origin and 20% of pre-Roman Gallaecian and Celtiberian, Germanic, Greek and Arabic origin.
Pre-Roman languages of Portugal
Traces of the languages from native peoples of western Iberia (Gallaeci, Lusitanians, Celtici or Conii) persist in Portuguese, as shown below. Most of the pre-Roman placenames or rivers in Portugal originate from the Hispano-Celtic Gallaecian and Celtiberian languages. There are also a few Iberian, Basque and Tartessian components in Portuguese.
List of Portuguese words of Iberian and Basque origin
Iberian-Basque
manteiga "butter" ***Uncertain origin, possibly Lat. mantica
Projections on Iberian vocabulary, toponyms and derivations in Portuguese, indicate just a few dozen words in total.
Basque
The Basque influence in Portuguese is believed to have entered mainly through Spanish, because many of those who took part in the Reconquista and later repopulation campaigns in Portugal, were of Basque lineage.
carrasco "executioner" or "Portuguese oak", from Basque karraska "thunder, crash of falling tree" sarna "scabies" from Medieval Latin (7th century, Isidore of Seville, Origines, 4.8.68), but as serna attested in Theodorus Priscianus (Constantinople, 4th century). however, after studying the variants of the word in the Latin medical treatises, proposes a Hispano-Celtic origin; cf. Middle Welsh sarn "mess" and sarnaf "to wreck".
Names of Basque origin
Forenames
Inácio variant of Ignatius. ***Of uncertain origin. Often claimed an Etruscan-Latinised derivation but probably Pre-Roman Iberian, Celtiberian or Basque see* Íñigo, ÍñakiVariants: Egnatius (Ancient Roman), Iñaki (Basque), Ignasi (Catalan), Ignác (Czech), Ignaas (Dutch), Iggy (English), Ignace (French), Ignatz (German), Ignác (Hungarian), Ignazio (Italian), Ignas (Lithuanian), Ignacy (Polish), Ignatiy (Russian), Ignac, Ignacij, Nace (Slovene), Ignacio, Nacho, Nacio (Spanish) Vasco derived from Basque "belasko", 'small raven' Xavier, from Basque Xabier, from etxe berri, meaning 'new house' or 'new home' Ximeno, a variant of the medieval Basque given name Semen, root seme < senbe 'son' as found in the ancient Aquitanian name Sembetten, attested form "sehi" as 'child', hypothetical ancient root *seni (cf. Koldo Mitxelena and modern form "senide" = 'brother or sister', 'relative')
Surnames
Velasco derived from Basque "belasko", 'small raven'
Celtic
Although there is not a comprehensive study or wordcount on how much Celtic, (particularly Gallaecian and words from the Hispano-Celtic group) survived in Portuguese (and Galician); it is fair to say that after Latin, this is the second largest component in the Portuguese culture and language. Projections on Celtic vocabulary (some words may have come via French borrowings starting in the 12th century), toponyms and derivations in Portuguese, indicate well over 1,500 words. The Celtic substratum is often overlooked, due to the strong Latinisation of Celtic-derived words in Portuguese.
List of Portuguese words of Celtic origin
Placenames
Names
Forenames
Surnames
A considerable number of the Portuguese surnames (spread in all Portuguese-speaking countries and ex-colonies today) is Celtic or of Latinised, Celtic-borrowings. This is not a comprehensive list of those.