what does "catch in her voice"mean?
He was hobbling away into the inner office, and did not hear the catch in her voice. The present was hidden at the bottom of his kitbag. It was very badly wrapped.
“Here,” he said. “This is for you. I couldn’t have done it without you.”
“Oh,” said Robin, on a strangled note, and Strike was both touched and faintly alarmed to see tears spill down her cheeks. “You didn’t have to…”
“Open it at home,” he said, but too late; the package was literally coming apart in her hands. Something slithered, poison-green, out of the split in the paper, on to the desk in front of her. She gasped.