In a conversation, one might want to stress that what one is going to say is related to what has been said (right) before.
In English, this can be achieved by starting a sentence with
By the way, ...
or
Speaking of <insert subject matter>, ....
or
Speaking of that, ...
In German, one would usually start a sentence with
Wo wir's gerade davon haben: ....
or
Apropos, ...
(The German word "apropos", like "apropos" in English, derives from the French "à propos". But other than the English one, it is AFAIK never used as an adjective in German, nor with prepositions as in English ("apropos of") or French ("à propos de").)
How is such a stress on the relatedness of the upcoming statement or topic to previous ones expressed in Esperanto conversation?
Speaking of that
=Pri tio
. On the German: apropos orübrigens=cetere (/krome)
.