Possible Clues:

• They're regularly taken with excessively sentimental speaker
• Pretty short period of time for speaker
• Robin, for one, gets part of speaker
• Stand unsteadily around with the little Speaker
• Pretty short name for piece of hi-fi
• 'Sentimentally pretty' three times on loudspeaker
• Loudspeaker - bird?
• Speaker's over-sentimental expression finally ignored
• Rather quaint short word for a loudspeaker
• Loudspeaker used to produce high-frequency sounds