Even though your little baby cannot speak, his/her body language or his/her voice tone expression can convey you to understand. You just keep taking care of him/her closely. The languages of each baby maybe different, but following are some languages that most babies at this age would normally do similarly.
Your baby wants to eat
For your newborn baby, whenever he/she is hungry, he/she will cry out loudly. So, it's not difficult to understand. He/she would normally require milks 2-3 hours for each meal.
Your baby wants to sleep
Your baby at this age will eat and sleep at the routine time. Eating and sleeping well is an important part of your baby's growth and development of his/her brain. Some babies can easily sleep, but some babies are difficult to sleep.
If your baby feels sleepy, but can hardly sleep by himself/herself, he/she will rub his/her face or eyes, pull his/her ears, pull blankets, pillow or dolls, etc. So, you have to hug him/her softly or sing lullaby songs till he/she sleeps.
Your baby does not feel comfortable
When your baby is sick, he/she does not feel comfortable and will show you immediately by crying loudly and non-stop. It will not be difficult to understand what's wrong with him/her if he/she has a fever or other significant symptoms. But sometimes, your baby may have a little cry because he/she feels exhausted. No matter whether your baby cries or not, you should call your doctor for any suggestion or take him/her to the hospital immediately.
Your baby wants the diaper changed
When the diaper is wet or get dirty, your baby feels uncomfortable and begins to cry out gradually louder until you come and change the diaper for him/her. If your do not change the diaper quickly, your baby's delicate skin may cause irritation. If it cause wounds on his/her skin, you baby will cry out more loudly.
These are only samples of your baby's body language and voice tone expression, there are many other kinds of signs which are not difficult to observe. If you take care of your baby closely, you will understand all.