spell speeds are not priority. though you do retain priority to activate a spell speed 2 or higher effect if it is your turn.
No Spell Speed: continuous monster effects effects, most continuous, equip and field spells and continuous traps after they are already activated.
Spell Speed 1: Ignition effects, normal, equip, field, and continuous spells
Spell Speed 2: Trigger effects, Quick Effects, quick-play spells, normal and continuous traps
Spell Speed 3: Counter Traps
obviously priority is only retained for spell speed 2 or higher effects, since spell speed 1 it must be your turn, and must be activated manually in an open game state
Basically during your turn, you retain priority to activate spell speed 2 or higher effects. for example. if you summon a monster, you allowed to activate your own torrential before your opponant can activate bottomless. if you pass turn player priority to your opponant and don't activate torrential, then they don't activate bottomless, priorty passes to you one last time. then if you acftivate something such as torrential, your opponant can now respond with bottomless again. if you don't activate torrential, the game state becomes open. neithe rplayer can respond to the summon any longer.
Another example is with inzektors, and this is my favorite example. Your opponant summons dragon fly. you allow it. they then equip hornet. the game state is open. your opponant, sinc eit is there turn, can activate spell speed 2 or higher effects, (hornet is spell speed 1), if they pass priority to you, you can compuls the dragon fly, making the hornet fall off, before the can activate hornet. dragon fly does not get it's effect since it is no longer on field (dragon fly is trigger in this case, where as equiping an inzektor would be igntion)
now spell speed are fun. spell speeds can only be responded to with the same spell speed or higher. the exception is spell speed one, as they cannot form chain links.
so your opponant activates a spell card. say rekindling (spell speed1). you respond with threatening roar (spell speed 2). your opponant wants to attack you this turn, so chain seven tools of the bandit (spell speed 3). you have no spell speed 3 cards set, so you are stuck with your opponants rekindling and their seven tools negating your roar. the chain resolves backwards, seven tools negates roar. roar tries to resolve but is negated. rekindling resolves, special summoning alot of flamvels/lavals.
the game state is now open, but the condition for a spell speed 2 torrential has been met. you activate torrential. they chain my body as a shield. both are spell speed 2, so this allowed. you can then chain something magic jammer to negate my body as a shield. the chain resolves backwards. magic jammer negates my body as a shield. my body as a shield tries to reolve but is negated. torrential resolves unhindered.
you understand now? if you need mor ehelp. here's a link to fast effect timing and spell speeds.
Priority overview (fast effects)
http://www.yugioh-card.com/en/gameplay/fasteffects_timing.htmlOffical rulebook (page 38-41 has chains, which should cover spell speeds as well)
http://www.yugioh-card.com/en/rulebook/index.html 
