Karen,
        A "bunched" tongue is a thick tongue due to low intrinsic muscle
tone.  Since the muscles are low in tone, they are more difficult to
activate/contract, and the infant expends more effort in sucking.  It may
also be difficult or impossible to latch on if the tone is very low.
        The posterior tongue elevation you decribe is sometimes called
"tongue humping".  I have seen this in babies who have restrictive
lingual frenula, especially if the attachment is slightly posterior to
the tongue tip.  Since the anterior tongue is unable to elevate, the
posterior tongue elevates alone.  This can cause nipple pain if the
nipple is bumped by the tongue, especially if there is recoil
(snapping down of the tongue from the restriction of the frenulum).
Children with this type of restriction often learn to use a sliding or
pistoning motion of their posterior tongue since peristalsis is
impossible.  I have also seen this elevation of the posterior tongue in
babies who are trying to defend their airways from fluid flow- fast
flowing bottles, forceful MER, or inability to configure their tongue
into a trough (groove) to collect milk into a bolus for holding and
controlled swallowing.  Cupping/grooving can be inhibited by a short
frenulum as well, as well as from low or high tone or neurological
difficulties.
        I was interested in your explanation of the "L" sounds in
English.  Is this why some kids say "yollipop"?  They can't get that
initial clear L, but can do the obscure one?
--
Catherine Watson Genna, IBCLC  NYC  [log in to unmask]