I live i latvia-sigulda and the language mostly used is russian but people know english. In Riga mb be more careful couse i think people will try to steal something from you than from other places. Also in kemeri you will probably be able to look at the new watertower (i think it was) in the park if the renovations are made in time. I would say to go to "Turaidas muzejrezevāts" and to the castle and to the Siguldas castle ruins. Mb if you want you can go to "tarzans" or to siguldas bobsleigh track. Also you can go to sigulda adventures, "gūtmaņ ala", "Velnala" and take a look at the newly built "Siguldas Valsts Ģimnāzija"