The thrust of this paper lies on semantic changes associated with additive and substitutive borrowing in Bantu-speaking communities in Tanzania. Due to contact of languages, semantic differences of the terms related to architectural structures emanate. Apart from data from a few elderly native speakers, research was carried out with the help of undergraduate students of linguistics. Further linguistic materials analysed herein come from dictionaries and lexicons. Although retention of the proto- Bantu words are apparent, findings indicate that cases of additive borrowing are obvious for new concepts associated with new architectural structures. The additive Swahili names incorporated into Tanzanian Bantu tend to designate specific concepts associated with modern (contemporary) architectural senses such as mulango ‘modern door’ vs. luigi ‘traditional entranceway’. Cases of substitutive borrowing are rare, as demonstrated by the Swahili word dirisha ‘window’ which replaces chitonono in Chimakonde, echihúru in Runyambo, ilituulo in Kinyakyusa etc.