We all know that a baby can't tell his needs or troubles in words. The only way for him to communicate with others is by crying. Babies show some other signs like feet kicking,hand waving and head turning ect.But the best way to take the attention of others is by crying.
Common reasons for crying:

1,Hunger:--
A hungry baby will cry till he gets the milk. Here the old saying comes true'crying baby gets the milk'.
2,Wetting:--
Urination and defecation causes some discomfort and results in crying till his parts are cleaned and made dry .
3,Company:--
Majority of the kids need somebody near. If they feel lonely they cry.When their favourite doll slips away from the grip they cry for help.
4,Tired:--
When the baby is tired after a journey and unable to sleep just cry simply.They feel tired in uncomfortable sourroundings and due to unhealthy climate.
5,Heat & cold:--
If they feel too hot or too cold they become restless and cry. Child is comfortable in a room with good ventilation.
6,Tight cloathing:--
Tight cloaths especially during warm climate is intolerable for kids.Tight elastic of the the dress can also produce soreness in the hip region.
7,Dark room:--
When the baby wakes up from sleep he needs some dim light.If there is darkness he will disturb the sleep of parents by crying.Ofcourse he will be irritated by strong light resulting in cry.
8,Mosquito:--
Yes,these creatures disturb the sleep by their blood sucking and make the baby to cry.
9,Nasal blocking:--
Child may not be able to sleep when there is a cold and go on crying till the passage is open.
10, Phlegm in throat:--
This also causes difficult breathing resulting in cry.Often a typical sound can be heard with each breath.
11,General aching:--
Generalised body ache with restlessness is seen in flu and prodromal stages of some infectious diseases can result in continuous cry.
12,Habitual cry:---Some babies cry without any real cause ending the parents in agony.Many a times doctor is called for help.
13,Nappy rash:-- If a tight and wet nappy is kept for a long time results in this conditon.
Rash can also be due to some allergic reaction to the elastic material of the nappy.
14,Earache:--
Ear infection is common in wet climate.The infection may spread from the throat.Ear infection can result in rupture of ear drum causing discharge of pus.Eareache usually becomes worse at night when lying down.Child will become restless with cry and may not allow you to touch the ear.Some children with earache rub the affected ear frequently.
15,Colic:--
When the baby cry continuously most of us diagnose it as colic.This roblem is still a topic for debate because exact cause for colic is not known and diagnosis is also difficult to confirm.Colic may be associated with rumbling and distention of abdomen.Child often feels better when lying on abdomen.Some children may not allow you to touch the abdomen.If the child cries continuously doctors help is needed.
16,Infections:--
All infections causes some kind of pain or irritation resulting in cry.Infection may be anywhere in the body.Usually it is associated with fever, redness and swelling.
17,Reactions to certain food:--
It is said that one man's food is another man's poison. Some food articles can produce some allergic reactions.Allergy is manifested in the form of redness, breathlessness,gastric symptons and continuous cry.
18,Hard stools:--
Constipated babies with hard stools may cry when they get the urge for stool.Some children hesitate to pass stool because of pain .
19,Gastro esophagial reflex:--
Here baby cries with spilling of food after feeding.If this continues it may be due to gastroesophageal reflex.This is due to failure of the lower part of esophagus to close after food causing regurgitation from the stomach.It is difficult to diagnose this condition and can be confirmed by giving antireflex medicines.
20, Dentition:--
During dentition child becomes restless with crying.Often associated with gastric troubles and diarrhoea.