What outdoor speaker can you recommend for outdoor tvs?
Without a site visit, any recommendations would be worthless. Consult a local professional.
Consult a local home theater installer.
You will need some type of receiver or amp between the TV and the speakers. That part will NOT be outdoor rated. Pretty much any outdoor rated speakers will work fine once you get the receiver/amp situation sorted out. https://www.amazon.com/Yamaha-NS-AW350W-All-Weather-Outdoor-Speakers/dp/B0001VHARY/ref=sr_1_4?ie=UTF8&qid=1549048749&sr=8-4&keywords=yamaha+outdoor+speakers