Sentence:  I was elected to the Executive Committee of the Vegetarian Society, and made it a point to attend every one of its meetings, but I always felt <WSD>tongue-tied</WSD>....And it was not a little curious that whilst others expressed their opinions at these meetings, I sat quite silent. Not that I never felt tempted to speak. But I was at a loss to know how to express myself. All the rest of the members appeared to me to be better informed than I. Then it often happened that just when I had mustered up courage to speak, a fresh subject would be started. This went on for a long time. 
Meaning of the word marked with <WSD> tags:  Unable to express oneself clearly or fluently; at a loss for words.