Possible Clues:

• Like the third letter of "talking"
• See 50-Across
• Saying nothing is kept up over period of religious observance
• Cold kind of treatment
• Like the opening letter of each of the four longest answers
• Like all pre-1927 movies
• Like three of the letters of 'aisle'
• Mum is upset ahead of religious period
• Like early 10s, one's rising fast
• With 63 Across, source of quote