where to live in Portugal and language (Lisbon)

I am planning a trip to Portugal to explore our options where to retire. We love the architecture of Lisbon and the vibe of an urban center. However, we are also avid tennis players and looking for friendly people who would like to play tennis. I am not necessarily seeking to live in an area where there are lots of expats. However, I am worried about the ability to make Portuguese friends as my Portuguese is not strong enough for communication and to make friendships (I am studying Portuguese now but it could be a years before I am fluent). Thus, I do not want to be too isolated. My question are two fold: 1) If my Portuguese is weak, will I feel left out and lonely even though many Portuguese speak English? Thus, should I abandon my desire to live in Lisbon and consider living in a bigger expat area such as Cascais and the Algarves (particularly Faro and Carvoeiro) which has good tennis)? My second question is there a city or town in Portugal that has good tennis and quaint cobble stone streets? I know this is probably the Algarves, but I am not a partier. Instead, I enjoy wandering through streets, culture and people. Thus, the Algarves may not be for me as the beach is not of primary importance and I am not looking for the next Cancun, Mexico or Miami Beach. Porto seems lovely and interesting, but I would prefer a sunny climate and worry that it could be more cold and rainy during the winter than Lisbon. Please inform me if I am wrong. Any suggestions to find the right fit would be great. Obrigado!!