In plain words
I am the father of this universe, the mother, the dispenser of the fruits of action, and the grandsire. I am that which is to be known, the purifier, Oṃkāra, and also the Rig, Sama, and Yajur Vedas.
Word for word
I [am] the father of this world, the mother, the dispenser, the grandfather; the knowable, the purifier, the syllable Oṃ, the Ṛk, the Sāman and the Yajus too.
पिताऽहमस्य जगतो माता धाता पितामहःवेद्यं पवित्रमोङ्कार ऋक् साम यजुरेव च
Other commentaries
The commentators
▸Bhagavadgītābhāṣyam
किञ्च —
पिता जनयिता अहम् अस्य जगतः, माता जनयित्री, धाता कर्मफलस्य प्राणिभ्यो विधाता, पितामहः पितुः पिता, वेद्यं वेदितव्यम् , पवित्रं पावनम् ओङ्कारः, ऋक् साम यजुः एव च ॥ १७ ॥
In plain words
And there is more —
Father: I am what begot this world. Mother: I am what carried it and brought it forth. Dhātā: I hand each living being the fruit its own action has earned. Pitāmaha: I am the father of that father. Vedya: I am what is there to be known. Pavitra: I am what makes clean — Oṃ. And the Ṛk, the Sāma, the Yajus: those too.
Close to the Sanskrit
Moreover —
Father — the begetter am I of this world; mother — the bearer; dhātā — the dispenser to living beings of the fruit of action; pitāmaha — the father of the father; vedya — that which is to be known; pavitra — the purifier, Oṃ; and the Ṛk, the Sāma, and the Yajus as well.