[7] The study of the substrate involves comparative methods applied to:[1] In general, words assumed to belong to substratum can be placed into two categories:[13][14] those related to nature and natural world and those used in pastoral life for: Other words from substratum are: bucur(ie), ciupi, copil, cursă, fluier, droaie, gata, ghiuj, jumătate, mare (adj), moş, scăpăra.
Words possibly of substratum but not generally agreed among linguists are: arichiță, băiat, băl, brâncă, orbalţ, borţ, bulz, burduf, burtă, codru, Crăciun, creţ, cruţa, curma, daltă, dărâma, fluture, lai, mătură, mire, negură, păstaie, scorbură, spuză, stăpân, sterp, stână, traistă.
[14] The comparative method can be extended to other languages of the Indo-European family, including ones from which Romanian could not have borrowed directly or indirectly, in order to reconstruct Thraco-Dacian substratum words.
a raised portion of land smaller than a hill and with abrupt sides) have almost identical correspondents in Albanian mal (mountain), but they can also be related to toponyms like Dacia Maluensis later renamed by Romans to Dacia Ripensis (rīpa - meaning bank, shore - has been inherited in Romanian as râpă - the abrupt side of a hill).
For example, the development of "ă" vowel: linguists Al. Phillipide and Grigore Brâncuș consider the spontaneous evolution of unstressed "a" from words like Lat.
cămașă, and stresses "a" before a /n/ or a consonant cluster beginning with /m/, a vowel found also in Bulgarian and Albanian, as the substratum influence in Romanian,[23] while linguist Marius Sala points this changes can also be seen as the tendency of the oral language to differentiate between forms of a paradigm, comparable to the development of similar central vowels in Portuguese or Neapolitan.