Echoed Voice is learned by 31 species by level, 212 by machine and 2 by egg

Effect, in PokéAPI's words

“Power increases by 100% for each consecutive use by any friendly Pokémon, to a maximum of 200.”

Who learns it

219 species in all, 5 of 9 games shown

Scarlet and Violet: 20 species

Species	Method	Level
Wigglytuff	Level up	1
Noctowl	Level up	1
Toucannon	Level up	1
Jigglypuff	Level up	4
Tandemaus	Level up	5
Maushold	Level up	5
Hoothoot	Level up	6
Pikipek	Level up	7
Chansey	Level up	8
Blissey	Level up	8
Minccino	Level up	8
Lechonk	Level up	8
Oinkologne	Level up	8
Cetoddle	Level up	9
Cetitan	Level up	9
Litleo	Level up	33
Pyroar	Level up	33
Meloetta	Level up	36
Cinccino	Egg
Trumbeak	Egg

Brilliant Diamond and Shining Pearl: 10 species

Species	Method	Level
Wigglytuff	Level up	1
Noctowl	Level up	1
Loudred	Level up	1
Exploud	Level up	1
Jigglypuff	Level up	4
Whismur	Level up	5
Hoothoot	Level up	6
Chansey	Level up	8
Blissey	Level up	8
Chatot	Level up	37

Sword and Shield: 18 species

Species	Method	Level
Wigglytuff	Level up	1
Noctowl	Level up	1
Loudred	Level up	1
Exploud	Level up	1
Tympole	Level up	1
Palpitoad	Level up	1
Seismitoad	Level up	1
Cinccino	Level up	1
Aromatisse	Level up	1
Drampa	Level up	1
Jigglypuff	Level up	4
Whismur	Level up	5
Hoothoot	Level up	6
Spritzee	Level up	6
Chansey	Level up	8
Blissey	Level up	8
Minccino	Level up	8
Arctozolt	Level up	14

Ultra Sun and Ultra Moon: 212 species

Species	Method	Level
Loudred	Level up, Machine	1, 4
Exploud	Level up, Machine	1, 4
Trumbeak	Level up, Machine	1, 7
Toucannon	Level up, Machine	1, 7
Drampa	Level up, Machine	1
Whismur	Level up, Machine	4
Pikipek	Level up, Machine	7
Hoothoot	Level up, Machine	13
Noctowl	Level up, Machine	13
Spritzee	Level up, Machine	13
Aromatisse	Level up, Machine	13
Minccino	Level up, Machine	33
Litleo	Level up, Machine	33
Pyroar	Level up, Machine	33
Meloetta	Level up, Machine	36
Chatot	Level up, Machine	37
Tympole	Level up, Machine	38
Palpitoad	Level up, Machine	42
Seismitoad	Level up, Machine	49
Bulbasaur	Machine
Ivysaur	Machine
Venusaur	Machine
Charmander	Machine
Charmeleon	Machine
Charizard	Machine
Spearow	Machine
Fearow	Machine
Pikachu	Machine
Raichu	Machine
Nidoran♀	Machine
Nidorina	Machine
Nidoqueen	Machine
Nidoran♂	Machine
Nidorino	Machine
Nidoking	Machine
Clefairy	Machine
Clefable	Machine
Jigglypuff	Machine
Wigglytuff	Machine
Diglett	Machine
Dugtrio	Machine
Meowth	Machine
Persian	Machine
Ponyta	Machine
Rapidash	Machine
Slowpoke	Machine
Slowbro	Machine
Doduo	Machine
Dodrio	Machine
Seel	Machine
Dewgong	Machine
Cubone	Machine
Marowak	Machine
Chansey	Machine
Jynx	Machine
Lapras	Machine
Eevee	Machine
Vaporeon	Machine
Jolteon	Machine
Flareon	Machine
Mew	Machine
Chikorita	Machine
Bayleef	Machine
Meganium	Machine
Sentret	Machine
Furret	Machine
Pichu	Machine
Cleffa	Machine
Igglybuff	Machine
Togepi	Machine
Togetic	Machine
Mareep	Machine
Flaaffy	Machine
Ampharos	Machine
Politoed	Machine
Espeon	Machine
Umbreon	Machine
Slowking	Machine
Misdreavus	Machine
Girafarig	Machine
Phanpy	Machine
Donphan	Machine
Smoochum	Machine
Miltank	Machine
Blissey	Machine
Lugia	Machine
Ho-Oh	Machine
Celebi	Machine
Torchic	Machine
Combusken	Machine
Blaziken	Machine
Mudkip	Machine
Marshtomp	Machine
Swampert	Machine
Zigzagoon	Machine
Linoone	Machine
Lotad	Machine
Lombre	Machine
Ludicolo	Machine
Taillow	Machine
Swellow	Machine
Wingull	Machine
Pelipper	Machine
Ralts	Machine
Kirlia	Machine
Gardevoir	Machine
Skitty	Machine
Delcatty	Machine
Plusle	Machine
Minun	Machine
Wailmer	Machine
Wailord	Machine
Numel	Machine
Camerupt	Machine
Swablu	Machine
Altaria	Machine
Chimecho	Machine
Absol	Machine
Spheal	Machine
Sealeo	Machine
Walrein	Machine
Rayquaza	Machine
Piplup	Machine
Prinplup	Machine
Empoleon	Machine
Starly	Machine
Staravia	Machine
Staraptor	Machine
Bidoof	Machine
Bibarel	Machine
Kricketune	Machine
Pachirisu	Machine
Buizel	Machine
Floatzel	Machine
Mismagius	Machine
Glameow	Machine
Purugly	Machine
Chingling	Machine
Happiny	Machine
Togekiss	Machine
Leafeon	Machine
Glaceon	Machine
Gallade	Machine
Dialga	Machine
Palkia	Machine
Giratina	Machine
Arceus	Machine
Tepig	Machine
Pignite	Machine
Emboar	Machine
Purrloin	Machine
Liepard	Machine
Pidove	Machine
Tranquill	Machine
Unfezant	Machine
Audino	Machine
Cinccino	Machine
Deerling	Machine
Sawsbuck	Machine
Elgyem	Machine
Beheeyem	Machine
Cubchoo	Machine
Beartic	Machine
Hydreigon	Machine
Reshiram	Machine
Zekrom	Machine
Kyurem	Machine
Fennekin	Machine
Braixen	Machine
Delphox	Machine
Froakie	Machine
Frogadier	Machine
Greninja	Machine
Flabébé	Machine
Floette	Machine
Florges	Machine
Pancham	Machine
Pangoro	Machine
Furfrou	Machine
Espurr	Machine
Meowstic	Machine
Amaura	Machine
Aurorus	Machine
Sylveon	Machine
Noibat	Machine
Noivern	Machine
Xerneas	Machine
Rowlet	Machine
Dartrix	Machine
Decidueye	Machine
Popplio	Machine
Brionne	Machine
Primarina	Machine
Yungoos	Machine
Gumshoos	Machine
Rockruff	Machine
Lycanroc	Machine
Comfey	Machine
Jangmo-o	Machine
Hakamo-o	Machine
Kommo-o	Machine
Tapu Koko	Machine
Tapu Lele	Machine
Tapu Bulu	Machine
Tapu Fini	Machine
Nihilego	Machine
Pheromosa	Machine
Magearna	Machine
Marshadow	Machine
Poipole	Machine
Naganadel	Machine
Zeraora	Machine

Sun and Moon: 209 species

Species	Method	Level
Loudred	Level up, Machine	1, 4
Exploud	Level up, Machine	1, 4
Trumbeak	Level up, Machine	1, 7
Toucannon	Level up, Machine	1, 7
Drampa	Level up, Machine	1
Whismur	Level up, Machine	4
Pikipek	Level up, Machine	7
Hoothoot	Level up, Machine	13
Noctowl	Level up, Machine	13
Spritzee	Level up, Machine	13
Aromatisse	Level up, Machine	13
Minccino	Level up, Machine	33
Litleo	Level up, Machine	33
Pyroar	Level up, Machine	33
Meloetta	Level up, Machine	36
Chatot	Level up, Machine	37
Tympole	Level up, Machine	38
Palpitoad	Level up, Machine	42
Seismitoad	Level up, Machine	49
Bulbasaur	Machine
Ivysaur	Machine
Venusaur	Machine
Charmander	Machine
Charmeleon	Machine
Charizard	Machine
Spearow	Machine
Fearow	Machine
Pikachu	Machine
Raichu	Machine
Nidoran♀	Machine
Nidorina	Machine
Nidoqueen	Machine
Nidoran♂	Machine
Nidorino	Machine
Nidoking	Machine
Clefairy	Machine
Clefable	Machine
Jigglypuff	Machine
Wigglytuff	Machine
Diglett	Machine
Dugtrio	Machine
Meowth	Machine
Persian	Machine
Ponyta	Machine
Rapidash	Machine
Slowpoke	Machine
Slowbro	Machine
Doduo	Machine
Dodrio	Machine
Seel	Machine
Dewgong	Machine
Cubone	Machine
Marowak	Machine
Chansey	Machine
Jynx	Machine
Lapras	Machine
Eevee	Machine
Vaporeon	Machine
Jolteon	Machine
Flareon	Machine
Mew	Machine
Chikorita	Machine
Bayleef	Machine
Meganium	Machine
Sentret	Machine
Furret	Machine
Pichu	Machine
Cleffa	Machine
Igglybuff	Machine
Togepi	Machine
Togetic	Machine
Mareep	Machine
Flaaffy	Machine
Ampharos	Machine
Politoed	Machine
Espeon	Machine
Umbreon	Machine
Slowking	Machine
Misdreavus	Machine
Girafarig	Machine
Phanpy	Machine
Donphan	Machine
Smoochum	Machine
Miltank	Machine
Blissey	Machine
Lugia	Machine
Ho-Oh	Machine
Celebi	Machine
Torchic	Machine
Combusken	Machine
Blaziken	Machine
Mudkip	Machine
Marshtomp	Machine
Swampert	Machine
Zigzagoon	Machine
Linoone	Machine
Lotad	Machine
Lombre	Machine
Ludicolo	Machine
Taillow	Machine
Swellow	Machine
Wingull	Machine
Pelipper	Machine
Ralts	Machine
Kirlia	Machine
Gardevoir	Machine
Skitty	Machine
Delcatty	Machine
Plusle	Machine
Minun	Machine
Wailmer	Machine
Wailord	Machine
Numel	Machine
Camerupt	Machine
Swablu	Machine
Altaria	Machine
Chimecho	Machine
Absol	Machine
Spheal	Machine
Sealeo	Machine
Walrein	Machine
Rayquaza	Machine
Piplup	Machine
Prinplup	Machine
Empoleon	Machine
Starly	Machine
Staravia	Machine
Staraptor	Machine
Bidoof	Machine
Bibarel	Machine
Kricketune	Machine
Pachirisu	Machine
Buizel	Machine
Floatzel	Machine
Mismagius	Machine
Glameow	Machine
Purugly	Machine
Chingling	Machine
Happiny	Machine
Togekiss	Machine
Leafeon	Machine
Glaceon	Machine
Gallade	Machine
Dialga	Machine
Palkia	Machine
Giratina	Machine
Arceus	Machine
Tepig	Machine
Pignite	Machine
Emboar	Machine
Purrloin	Machine
Liepard	Machine
Pidove	Machine
Tranquill	Machine
Unfezant	Machine
Audino	Machine
Cinccino	Machine
Deerling	Machine
Sawsbuck	Machine
Elgyem	Machine
Beheeyem	Machine
Cubchoo	Machine
Beartic	Machine
Hydreigon	Machine
Reshiram	Machine
Zekrom	Machine
Kyurem	Machine
Fennekin	Machine
Braixen	Machine
Delphox	Machine
Froakie	Machine
Frogadier	Machine
Greninja	Machine
Flabébé	Machine
Floette	Machine
Florges	Machine
Pancham	Machine
Pangoro	Machine
Furfrou	Machine
Espurr	Machine
Meowstic	Machine
Amaura	Machine
Aurorus	Machine
Sylveon	Machine
Noibat	Machine
Noivern	Machine
Xerneas	Machine
Rowlet	Machine
Dartrix	Machine
Decidueye	Machine
Popplio	Machine
Brionne	Machine
Primarina	Machine
Yungoos	Machine
Gumshoos	Machine
Rockruff	Machine
Lycanroc	Machine
Comfey	Machine
Jangmo-o	Machine
Hakamo-o	Machine
Kommo-o	Machine
Tapu Koko	Machine
Tapu Lele	Machine
Tapu Bulu	Machine
Tapu Fini	Machine
Nihilego	Machine
Pheromosa	Machine
Magearna	Machine
Marshadow	Machine