"when it is done" (tense) and "how it is done" (mood, voice). The Indo-European languages differ in the detail. For example, the Sanskrit language attaches the affixes and ending to the verb root, while the English language adds small independent words before the verb. In Sanskrit, these elements co-exist within the word. Both verbs and nouns in Sanskrit are either thematic or athematic, states Jamison. Guna (strengthened) forms in the active singular regularly alternate in athematic verbs. The finite verbs of Classical Sanskrit have the following grammatical categories: person, number, voice, tense-aspect, and mood. According to Jamison, a portmanteau morpheme generally expresses the person-number-voice in Sanskrit, and sometimes also the ending or only the ending. The mood of the word is embedded in the affix. These elements of word architecture are the typical building blocks in Classical Sanskrit, but in Vedic Sanskrit these elements fluctuate and are unclear. For example, in the Rigveda preverbs regularly occur in tmesis, states Jamison, which means they are "separated from the finite verb". This indecisiveness is likely linked to Vedic Sanskrit's attempt to incorporate accent. With nonfinite forms of the verb and with nominal derivatives thereof, states Jamison, "preverbs show much clearer univerbation in Vedic, both by position and by accent, and by Classical Sanskrit, tmesis is no longer possible even with finite forms". While roots are typical in Sanskrit, some words do not follow the canonical structure. A few forms lack both inflection and root. Many words are inflected (and can enter into derivation) but lack a recognizable root. Examples from the basic vocabulary include kinship terms such as mātar- (mother), nas- (nose), śvan- (dog). According to Jamison, pronouns and some words outside the semantic categories also lack roots, as do the numerals. Similarly, the Sanskrit language is flexible enough to not mandate inflection. The Sanskrit words can contain more than one affix that interact with each other. Affixes in Sanskrit can be athematic as well as thematic, according to Jamison. Athematic affixes can be alternating. Sanskrit deploys eight cases, namely nominative, accusative, instrumental, dative, ablative, genitive, locative, vocative. Stems, that is "root + affix", appear in two categories in Sanskrit: vowel stems and consonant stems. Unlike some Indo-European languages such as Latin or Greek, according to Jamison, "Sanskrit has no closed set of conventionally denoted noun declensions". Sanskrit includes a fairly large set of stem-types. The linguistic interaction of the roots, the