Sentence:  In the following year her father undertook to give a course in Hebrew theology to Johns Hopkins students , and this brought to the Szold house a group of bright young Jews who had come to Baltimore to study , and who enjoyed being fed and mothered by Mamma and entertained by Henrietta and Rachel , who played and <WSD>sang</WSD> for them in the upstairs sitting room on Sunday evenings . 
Meaning of the word marked with <WSD> tags:  produce tones with the voice