visual filter

It's often a good idea to start from a search window

In this case using the search string speaker:Jesus

Then save that as a visual filter

https://support.logos.com/hc/en-us/articles/360016747431-Create-a-Visual-Filter#create-a-bible-visual-filter also provides an overview of how to do this.

Sorry, seems not to work for me. Do I have to upgrade to some higher level package in order to get results searching for "speaker" ?

You need the Starter Feature Upgrade or higher.