Legal Question in Civil Litigation in California

Re: personal loan

If you made the recording without your co-worker's knowledge and consent, then it will not be admissible in your lawsuit against him. More importantly, surreptitiously recording a private conversation is a crime. If you are prosecuted, the recording will be admissible against you.

Many laypeople don't realize that testimony is a form of evidence. If you testify that you lent your co-worker this money, that may be enough to prove that it happened. Most defendants would not be willing to commit perjury in order to deny something like this. If your co-worker does deny it, you may need additional evidence like records of him paying off $1,100 worth of bills at the time you made the loan. Even if you can't get such evidence, the judge or jury (this should probably be a small claims case, and there are no juries in small claims court) may find you more credible and accept your word over his.

Good luck.

Re: personal loan

Unless he consented to the recordings you might want to be very careful about using them.

I'd just take him to small claims court. You testimony is enough. Try to back it up with a bank statement showing the $1,100 withdraw. An independent witness might also be useful.