Dialects in my family

I’ve noticed an interesting facet of the Telugu language. The language has various regional dialects. These dialects often use very different words for certain objects. For example, take the word “bedsheet.”. My maternal grandfather, who is from Dorigallu would use the word “pacharam.” However, my maternal grandmother, who is from Pulivendla, uses the English word “bedsheet” even when speaking in Telugu. This seems like a simple case of colonial British rule influencing the local language. However, there are other cases which aren’t as clear.  For example, take the Telugu word for “habit.” My paternal grandfather, uses the word “rudi” whereas the rest of my family uses the word “alavatu.” This is a more interesting phenomenon as both of these words are Telugu words. I wonder if there is a deeper reason for this. Was “rudi” a word that originated from a similar Dravidian language? Usually, dialects form due to forced isolation between areas, such as geographic barriers or large distances. For example, French Quebec developed its own dialect due to it being an overseas colony with little connection to mainland France. However, that doesn’t seem to be the case here. All four villages where my grandparents are from are in an approximately 25-mile radius, and trade and communication between the villages is common due to the lack of geographic barriers. This makes me wonder what is the reason for the development of distinct dialects despite so much communication.