In Mark 2:2 in the NET and several other versions the Greek laleis as "preach":
“…and he preached the word to them.” (Mark 2:2 NET)
“…And he was preaching the word to them.” (Mark 2:2 ESV)
“…and he preached the word to them.” (Mark 2:2 NIV11)
However, the word does not mean "preach." It means to "babble, chatter, speak." The NRSV and others get this right:
“…and he was speaking the word to them.” (Mark 2:2 NRSV)
“…and he was speaking to them the word” (Mark 2:2 YLT)
“…and he began speaking the word to them.” (Mark 2:2 MOUNCE-NT)
"…and he–was–telling them the word." (SIL Exegetical Commentary)
There are times that Jesus is announcing/proclaiming (Greek kērussō) the Good News, but in this case, the Greek has him speaking/telling/chatting with them about the message while sitting in a house.