Commonly used teething toys restrict tongue movement and can interfere with a baby&amp;#39;s ability to distinguish between two different sounds, &amp;lt;a href=&amp;quot;http://www.pnas.org/content/early/2015/10/06/1508631112.abstract&amp;quot; target=&amp;quot;_blank&amp;quot;&amp;gt;according to a study&amp;lt;/a&amp;gt; published by the Proceeding of the National Academy of Sciences. Listening to sounds is not the only driving factor of speech perception and language acquisition for infants, the research showed. Six-month-old infants who had free tongue movement, as opposed to infants who were given teethers that restricted the movement, were able to make better distinctions of speech sounds. It seems that baby talk is beneficial for infants beyond the joy of babbling.  -- Viola Lanier 