That is my personal issue.

We are going on a trip together.

I lost my precious belongings.

He loves playing string instruments.

He was fascinated by the beautiful timbre of string music.

He is asking for a reduction in taxes.

He is thinking of tax-saving measures to reduce his taxes.

He is an expert in sociolinguistics.

I am very interested in sociolinguistics.

He is an expert in natural language processing.