o i was wondering what frequency do i need to run those chips to achieve listenable audio signal, and is the 4 MHz frequency (from attiny) enough?
4MHz is overkill for audio (Typical bandwidth of audio is 20kHz)However, assuming you plan on using the Tiny's own ADC to sample the audio, you won't be able to achieve much better than telephony quality (3kHz bandwidth)
does that mean that i can get the 20kHZ frequency?
Admittedly I haven't looked in detail at the chips you provided links for, but one thing to keep in mind, whenever you use a chip that may be a bit more specialized, always first check availability and price before committing any time or effort to a design that uses the part.
That would be a good RAM for Storing data.Your code will not execute from that RAM tho - only from the internal SRAM, the 128 bytes in a '2313 that are used for registers and stuff.