Why the shloka still works
On the strange durability of two-line Sanskrit verses, and what makes them harder to forget than the prose around them.
There is a reason the Indian tradition packaged its deepest knowledge into shlokas — short metric verses of two lines, each line eight syllables, each pair held together by an internal music that survives translation, distortion, and three thousand years of partial memory.
The shloka is a form, not a content. The content can be anything: a teaching of Krishna, a description of a goddess, an instruction to a student, a curse on an enemy. The form is the same: 32 syllables, four pādas of eight, a particular rhythmic skeleton that the Sanskrit grammarians called the anuṣṭubh metre.
Why does this form work?
The first reason is mnemonic. Eight syllables is the limit of what working memory can hold as a single chunk. Pair two of them — sixteen syllables — and you get the longest unit a human voice can comfortably deliver in one breath. Pair two breaths and you have the shloka. The form was reverse-engineered from the body's natural rhythms; this is why it is easy to memorise and harder to forget than the same content in prose.
The second reason is structural. Two lines means you can do call-and-response: the teacher speaks the first line, the student finishes the second. Most of the Gita is built this way. So is the Yoga Sutra. So are the conversational sections of the Upanishads. The shloka is a teaching tool — a way to encode a doctrine in a unit that can be passed back and forth between two voices.
The third reason is poetic. Once you start writing in anuṣṭubh metre, certain phrasings become almost inevitable. Compound words have to break in particular places. Endings have to fall on certain syllables. The form forces a sparseness on the writer that prose does not. The result is verse that sounds, even in translation, denser than ordinary language.
Try this experiment. Read the shloka 'Karmaṇy-evādhikāras te' (Bhagavad Gita 2.47) out loud, slowly, in Sanskrit. Notice how the meter wants to carry you forward. Now read the English translation — 'You have a right only to action, never to its fruits' — and notice how the same idea, in prose, is forgettable.
This is why we cannot, as a culture, simply translate the shlokas and move on. We have to keep them. Recite them. Sit with them. The form is doing work that the content alone cannot.
The good news is that you do not need to learn Sanskrit to feel this. Most of the major shlokas have been recorded by chanters whose lineage goes back to the original oral tradition. Listen to a Vedic chanter read the Gāyatrī mantra; you will feel the form before you understand the content. That is the order in which the tradition is meant to be received.