Why does Bitcoin uses a Script language? From what I heard is that Bitcoin use Script to verify transactions (I'm probably wrong).

Wouldn't be sufficient just signing the transaction with the private key and append the signature to the transaction? This way everyone could verify if the transaction was sent form that public key.

Is this insecure?

I imagine that Script is used for other things too. But If I only wanted to verify the transaction, I could do it with a simple signature right?

Thanks
Yes it does use a language called script. The transactions have both a locking and unlocking script and it is there to allow the specification of simple conditions for spending so that transaction validation is not based on a static pattern and allows the spending of money to be programmable. The locking script normally contains the public key hash while the unlocking script normally contains a digital signature. The scripting language also caters for more complex multisignature scripts. If you just limited the processing to a signature verification then it would not allow for richer functionality and multisignature functionality.