I noticed that i can exert less tension while speaking by simply focusing on my vocal cords and saying stuff with less tension. This does help to a certain extent and might be perfected to speak in this way 24/7 since that is what effortless speech feels like for me, do you have experience with this? Try to say a word with a lot of tension and then say it with NO tension at all while focusing on your vocal area and see if you feel any difference. The only con of this method is that speaking becomes somewhat of a conscious thing and that sucks.