Start of a Morse Code lab... I basically smashed two Adafruit guide demos together. Transition state machine approach now calls sample.play and sample.stop at the right times.

code.py

from digitalio import DigitalInOut, Direction, Pull
import audioio
import board
import array
import time
import math

FREQUENCY = 440    # 440 Hz middle 'A'
SAMPLERATE = 8000  # 8000 samples/second, recommended!

# Generate one period of sine wav.
length = SAMPLERATE // FREQUENCY
sine_wave = array.array("H", [0] * length)
for i in range(length):
    sine_wave[i] = int(math.sin(math.pi * 2 * i / 18) * (2 ** 15) + 2 ** 15)

# enable the speaker
spkrenable = DigitalInOut(board.SPEAKER_ENABLE)
spkrenable.direction = Direction.OUTPUT
spkrenable.value = True

sample = audioio.AudioOut(board.SPEAKER, sine_wave)
sample.frequency = SAMPLERATE
 
led = DigitalInOut(board.D13)
led.direction = Direction.OUTPUT
 
button = DigitalInOut(board.BUTTON_A)
button.direction = Direction.INPUT
button.pull = Pull.DOWN
 
output_state = False
while True:
    if output_state == True:
        if button.value == False:  # button is pushed
            led.value = False
            sample.stop()           # we tell the board to stop
            output_state = False
    else:
        if button.value == True:
            led.value = True
            sample.play(loop=True)  # keep playing the sample over and over
            output_state = True
            
    time.sleep(0.01)