One of the reasons that consonant nouns can be so confusing is that they use multiple stems. The word yogin, for instance, uses one stem in case 1 and another in case 4. These stems follow strict patterns and are quite simple to use; but regardless it can be difficult to come to terms with them. For that reason, let's start here with those consonant nouns that use only a single stem. All of the nouns we've seen so far use only one stem, too.
Even though we are talking about the one-stem consonant nouns, each of these nouns usually has two forms. One form is used in front of vowels only; this is the regular stem as listed in the dictionary and in vocabulary pages. But the other stem is used in every other circumstance: that is, it's used in the case 1 singular and in front of consonants. This "second" stem is a product of complex sandhi changes from the first one.
वाच् + अम् → वाचम्
vāc + am → vācam
speech (case 2 singular)
वाच् → वाक्
vāc → vāk
speech (case 1 singular)
Instead of studying these sandhi changes in detail, let's just learn these two forms separately for now. By doing so, we can learn the sandhi rules over time while still maintaining a full knowledge of the consonant nouns.
Now, let's look at a full example of a consonant noun. For our example, let's use dhanus, which is a neuter noun that means "bow (weapon)." Its "second" stem is dhanuḥ, which follows all of the rules that a word like naraiḥ does. Given these two stems, we can fill in the table for dhanus as follows.
The behavior of this noun may seem irregular. However, all of the "irregularities" here are caused by regular sandhi changes. None of these changes should be unfamiliar. Note, too, the presence of the "inserted nasal" sound in the plural of cases 1, 2, and 8.
The change from ns to ṃs was first seen in the lesson on the ordinary future tense.
Most of the external sandhi changes that apply to the consonant nouns can be explained with some familiar rules:
- A final stop will take the voice of the letter that follows it.
- A final stop will become nasal if followed by a nasal consonant. It will keep its own point of pronunciation.
वाक् च → वाक् च
vāk ca → vāk ca
वाक् देवी → वाग् देवी
vāk devī → vāg devī
Speech is a goddess.
वाक् एव → वाग् एव
vāk eva → vāg eva
वाक् न → वाङ् न
vāk na → vāṅ na
Note that k and ṅ have the same point of pronunciation.
Now, recall this rule of -t sandhi:
When followed by h, t becomes d and h becomes dh. We can state this rule more generally:
When followed by h, a consonant becomes voiced. h becomes a stop consonant with the same point of pronunciation.
वाक् हि तस्मिन् भवति → वाग् घि तस्मिन् भवति
vāk hi tasmin bhavati → vāg ghi tasmin bhavati
For speech is in him.