Going to review based on reading the class, though my opinions may change if I actually experience the abilities in play.
Base Class: Change saves to either Wis/Cha or Wis/Int. Cha and Int are both two of the "Lesser" saves, so having two of those is a little underwhelming. While I don't think multiple concentration is TOO bad, I think limiting it to certain spells or combinations of spells would help eliminate the fringe cases where a broken combination could be found. Also, cantrips as a bonus action is pretty strong, outright doubling the damage output of the class over other spellcasters, but I think it can work. Starting with 5 cantrips and building up to 7 is a bit much, I'd cull that down toa start of 2 or 3 with a max of 5 or 6, including Spirit Strike.
Bonespeaker: Branch spells fit the "necromantic" theme, no complaints here. Though I'd say for this and all other subclasses limit the Subclass spells to 5th level and lower to keep to the standard set by other classes. Gravewalker and Channel the Lost both seem fine and fit the flavor. Bone Shield is crazy damage reduction over the course of a fight, consider maybe changing this to a set amount of Temp HP? Whispers of the Damned is a good ribbon, though I think changing out Intimidation for History or some other knowledge skill might make a little more thematic sense. Greeting Death as a Friend is a good ability, and causing death upon destruction is a good trade-off for making the already extremely tanky subclass even MORE tanky (50% more hitpoints, combined with resistance AND Bone Shield? Oh my.) Eternal Communion is something you need to be careful with, changing subclass to undead is very damaging, as many healing spells do not effect creatures of the Undead type. I'd also reconsider the ability to reform after death, changing it to revival spells not needing material costs when uses on this character ala Zealot.
Cityspeaker: The spell selection and level 1 abilities all seem good and flavorful for the "Street Level" Shaman, maybe also cause an int save prof to change to Cha save prof for this subclass (if you make Wis/Int the standard for the class) or grant Cha saves in addition to Wis/Int at a higher level. Tangled Streets might be stepping on the Ranger's toes a bit, but I don't think it's unfitting for the subclass, maybe limit the benefits to cities you are intimately familiar with? Mob Mentality needs a little clarification, maybe "When one enemy is within 10 feet of you and another enemy moves within 10 feet you can...", to eliminate the case of you moving into the appropriate range on your turn and then using your reaction to move further. Voice of the Masses needs a usage limit, Max Damage isnt something to be scoffed at, if you want an unlimited usage version perhaps dice re-rolling is better than always-on max. Risen Metropolis I love this ability, though the need to roll a Nat 20 for it to function is strange, maybe just allow it as an action on your turn once per day?
Lifespeaker: Good spell list, Good level 1 abilities. Again, consider the "Change int save to cha save prof" ability, if you go that route. Spring to Life is odd to say the least, advantage on death saves is fine, but moving while unconscious seems very odd to me. Lively Rituals now I dont know if I'm mistaken, but I believe you already CAN cast ritual spells while moving. The half-time portion is great though! Dance til you Drop maybe allow this to be an Insight check rather than just generic Wisdom? or a Wisdom Save? also it being a Stun effect on a Natural 1 is out of tune with other abilities in the game, as it's the only effect where a natural 1 on a save/check means something. Beacon of Life is insane healing! Better than a Life Cleric! Maybe limit this to half or quarter of max hit dice per usage?
Stringspeaker: Good spell selection. Force damage is a pretty strong damage type, but I don't think it's too strong to give out on a cantrip level. Voodoo could use a bit of wording change, maybe "you give the ally resistance to the triggering damage, and the attacker takes an equal amount of damage that cannot be reduced in any way". Channel the Weave is great, and I love it, maybe make the ability increase in accuracy depending on if you just have a name vs a piece of the creature/item. Bad Juju is a good ability, but perhaps a bit strong. Maybe change it to Disadvantage on saves using the ability they have check disadvantage on, rather than ALL saves. Voodoo Doll is good, though i'd maybe change it to "You control their movement and actions on their next turn" instead of just one or the other? Might be a bit too strong in that case...dunno. Mojo Advantage on attack rolls for all attacks made by all allies? Wow! Consider making this a full action ability. String Theory is crazy strong and opens up a lot of abuse cases. Have your party gang up on a friend to reduce them to 1 or 0, then swap that allies HP with the big bad, proceed to one shot him.
Wildspeaker: Very druid-like spell list, I like it. Damage choices are nice on the cantrip, maybe add Fire too to complete the "natural" type trifecta? Savage Spirits is fine, though I don't think the extra damage is really necessary. Channel Nature all good abilities, though "Base AC" is a bit confusing, just change it to "+2 to AC when wearing no armor or Light armor" if thats your intention, or "Your AC cannot be lower than 12" if that was your intention. Animal Preference fine ribbon. Permanent Savagery choice of permanent effect of the list is great, having 2 effects at a time is even greater! Cycle of Life Good ability, though maybe clarify if you mean the damage the attack actually dealt, or the damage the creature took (in cases where this is a different number). Worldrage love the ability, almost like a new spell! I might change it to half-damage and no restrain on a save rather than what it is, but I'm not sure on that one!
Overall I like the class, though it needs a few changes to bring it in line with typical class standards, and maybe reduce the power of some of the standout abilities.
