Nouns and declensions in Sanskrit - I

Sanskrit is heavily inflected languages. In Sanskrit, noun ending change depending on how the noun is used.

These noun endings called cases are the following

1. nominative - subject of sentence
2. accusative - object
3. instrumental - by/from/with
4. dative - to
5. ablative - from (away from)
6. genitive  - possessive - of
7. locative - in - indicating location
8. vocative - calling

In Sanskrit these are called vibhakti and are given numbers one to eight. prathama vibhakti is nominative, dvitiya is accusative and so on.

There are other Sanskrit names for these also. Except for Genitive, the rest of the cases are called कारक

1. Nominative - कर्तृ
2. Accusative - कर्म
3. Instrumental   - करण
4. Dative - सम्प्रदान
5. Ablative - अपादान
6. Genitive -    सम्बन्ध
7. Locative - अधिकरण
8. Vocative - सम्बोधन​  

What do all these mean actually?

1. राम​: गछति  | प्रथमा 
• The word राम​: is in प्रथमा विभक्ति. 
• Also remember that, this noun can be in singular, dual or in plural - which are रामौ (two ramas) रामा: (ramas)
2. अहं रामं नमामि| 
• I pray to Rama.
• Here Rama is the object of the sentence. So it is द्वितीया विभक्ति - कर्म
3. रामेण रावण​: हत​:|
• By Rama, Ravana is killed. 
• Rama is instrumental. By him killing was done. So  रामेण is तृतीया  विभक्ति or करण
4. रामाय पुस्तकं ददामि|
• I give book to Rama. 
• Here Rama is in dative case. We are using "to Rama". This is चतुर्थि विभक्ति  or sampradhana
5. रामः नगरात् आगच्छति|
• Rama comes from the city. 
• Here the word  नगरात् is in ablative case. This is पंचमि विभक्ति or apadana
6. रामस्य माता कौसल्या|
• Rama's mother is Kausalya
• Here रामस्य is in genitive case - of Rama - It is shashti vibhakti or sambandha
7. रामः नगरे अस्ति|
•  Rama is in the city.
• Here  नगरे is in locative case - in the city - it indicates situation of location. This is सप्तमी विभक्ति or adhikarana
• 
  
8. हे राम, अत्र आगछ |
• Rama come here.
• Here we are calling Rama. It is vocative case - sambodhana 

Here is the complete table which includes dual and plural cases also.

prathama राम: रामौ रामा:
dvitiya      रामं रामौ रामान्
tritiya        रामेण रामाभ्याम् रामै:
chaturthi   रामाय रामाभ्याम् रामेभ्य​:
panchami रामात् रामाभ्याम् रामेभ्य​:
shashti     रामस्य रामया: रामाणाम्
saptami    रामे रामयो: रामेषु
sambodhana हे राम हे रामौ हे रामा:
 
 And the story does not end yet.

Not all the words have endings like rama shabda.

 

 Only masculine words which end with akara have declensions like Rama. For ikaranta, ukaranta etc, the tables are completely different. Do not worry so much about that. Just know the general rules.

Now to end it all, let us have some exercises. Find out the vibhakti of the words in bold.

1. उद्यमेन एव सुखं भवति | There is happiness only with hard work.
2. एतत् मम पुस्तकं अस्ति| this is my book.
3. स​: अश्वं पश्यति। He sees the horse
4. उद्याने पुश्पाणि सन्ति| There are flowers in the garden
5. स​: पन्डित​: कुत्र अस्ति | Where is that learned man?
6. राम: फलं भक्षयति| Rama eats the fruit
7. किं त्वं प्रतिदिनं भ्रमणाय गच्छसि| You go for walking every day.
8. मया ब्राह्मणाय मोदकं अर्पित​:| Sweet was given by me to Brahman
9. स​: मित्रेण सह भाषणं करोति| he is talking with friend
10. बाल​: मार्गे क्रीडति| Boy is playing on the road
11. त्ृषिताय मनुष्याय जलं देहि| Give water to thirsty man
12. मया रामस्य वार्ता अपि न श्रुता| I haven't heard news of Rama.
13. जना: मुनिं न निन्दन्ति| People do not scold the sage.