"I try to talk."
Translation:Ik probeer om te praten.
For the infinitive 'proberen', or 'to try', you can use 'om' but it is one of those cases where 'om' can be omitted, which people tend to do. Thus, using 'om' here would be unusual, but not wrong.
See more information about the infinitive constructions and the situation with 'proberen te' here. :)