A short vowel is substituted in the Vocative Case singular for the final ā of the feminine affix, in the sense of 'mother, mother-dear' and also for the long vowel of the feminines called nadī -- yū stryākhyau nadī [[1.4.3]] etc.,
As अम्ब ! हे अक्क ! हे अल्ल ! हे कुमारि ! हे शार्ङ्गरवि ! हे ब्रह्मबन्धु ! हे वीरबन्धु !
Vart:- Prohibition must be stated when the endearing terms denoting mother have an uncombined उ, ल or क, as हे अम्बाड ! हे अम्बाल ! हे अम्बिक ! But हे अक्क and हे अल्ल where the ल and क are conjunct.
Vart:- Optionally so in the Veda: as हे अम्बाड ! or हे अम्बाडे ! हे अम्बाल ! or हे अम्बाले, हे अम्बिक ! हे अम्बिके ॥
Vart:- A feminine stem formed with the affix तल् optionally becomes short before the Vocative Singular and Vocative Singular. As देवते भक्तिः or देवतायां भक्तिः, हे देवत ! or हे देवते ॥ This shortening takes place in the Veda only.
Vart:- In a Bahuvrihi compound ending with मातृ, there is substituted मात for मातृ in the Vocative Singular when the word means a son worthy of such a mother. As हे गार्गीमात ! = मात्रा व्यवदेशमर्हति श्लाघनीयत्वाद् यः पुत्रः ॥ This debars the कप् affix of 5.4.153. The च् of मातच् makes the final acute.,