To utter words indistinctly or in a low tone, often as if talking to oneself or to complain.
Mutter
To utter a loud, sharp, shrill cry.
Shriek
Able to express oneself fluently and coherently.
Articulate
To learn by heart.
Memorise
To stray from a path, place, idea...etc.
Wander
Mental hold or capacity, power to understand, comprehension.
Grasp
Tu utter a low, usually nasal, complaining cry or sound, as from discontent.
Whine
To bring back from memory.
Recall
To have a natural ability for doing something.
Have a gift for
To let out one's breath audibly, as from sorrow, weariness, or relief.
Sigh
To talk softly and privately.
Whisper
A sudden short intake of breath, as in shock or surprise.
Gasp
Completely puzzled or confused, perplexed.
Bewildered
To became aware of, to recognize, discern or understand.
Perceive
To cry out or speak with a strong, loud, clear sound; shout.
Yell
To utter a low, deep soung expressive of pain, grief, disapproval or desire.
Groan