A propósito

Place it at the very start of your sentence to introduce a new point. You can also use it mid-sentence to add a detail you almost forgot. If someone says something that reminds you of a task, drop an a propósito right there. It acts as a linguistic 'pause button' before you change the subject slightly. It is incredibly versatile for both speaking and writing.

You will use this constantly in daily life. Use it at a restaurant when you suddenly remember you need extra napkins. Use it in a business meeting to bring up a related project. Use it while texting a friend to mention a party this weekend. It works perfectly when the new topic is loosely connected to the current one. It is the ultimate tool for the 'oh, I almost forgot' moments.

Do not use it to interrupt someone who is in the middle of a deep, emotional story. That would feel dismissive. Avoid using it if the new topic is completely, 100% unrelated to anything said before. In those cases, mudando de assunto (changing the subject) is better. Don't overthink it, but don't use it as a filler word every three sentences. It loses its impact if you say it too much.

Portuguese speakers value smooth social transitions. We don't like to jump randomly from topic to topic without a 'bridge.' A propósito provides that polite social glue. It shows you are engaged but also have more to contribute. It reflects the conversational nature of Brazilian and Portuguese cultures. We love to weave stories together, and this phrase is the needle.

You might hear por falar nisso, which means 'speaking of which.' It is slightly more informal than a propósito. Another one is aliás, which is very common and means 'furthermore' or 'actually.' If you want to be very casual, you can just say ah, e... (oh, and...). However, a propósito remains the most balanced and elegant choice for most situations.