Is there a particular reason this word seems difficult to pronounce? Many Latin sounds cannot be accurately represented in terms of English sounds, but it would be roughly pronounced:
cone-sehr-WAH-wee
Second, I want to use words in sentences of my own. Can you use a verb like this?
Peccare cogitant.
They plan to sin.
Yes, this is a legitimate use for cogito, -are. Making up your own sentences is key to developing the ability to generate good Latin text, and thinking in Latin. You do have to be somewhat cautious about using words in particular ways, since the Latin custom may be different, but you were right this time.
Some examples from real writers (thanks L&S):
cogitat recipere hunc in aedes, -Terence
“he intends to receive him into his house”
_____ deducere exercitum_, -Suetonius
“(plan) to lead the army away”
_____ praedium parare_, -Cato
“(intend) to prepare the estate”
_____ cenare_, -Cicero
“(plan) to have dinner”
Thanks and I’m sure this is the first of many questions!