1♣ = natural, or 11-14 balanced without 4 diamonds, or any 18- bad 20 balanced (including those with 5 diamonds)
1♥ = 4+ spades, may be very light
1♠ = unbalanced with 3 spades, or a hand that would have rebid 1NT in the standard auction 1C - 1S - ?
2♣ = sign-off in 2D, or invitational with 5 spades, or some game forces
2♦ = poor clubs, not the unbalanced spade raise
At the other table the auction was
1♣ - P - 1♥ - P
1♠ - P - P - 1NT
P - 3NT all pass
(first 3 bids had much the same meanings as at our table)