Lol get the reference:)

This is a fun magic item to use as a player but a terrible item to give to a player as a DM, let me explain. Most people get this as a longsword which is good for players but a hell for DM's, imagine this your players are fighting an enemy and the fighter pulls out this, the problem is that since it's a versatile weapon they're now dealing five additional points of damage when they attack and get a +1 bonus to ac without a shield. Now they're dealing 2d6 fire damage, 1d8 slashing damage, 1d10 for regular damage, +5 to damage rolls, +2 to damage rolls as well (if proficient), versatile weapons allow you to use your strength modifier on your attack rolls, and since versatile weapons aren't heavy you can use this as a small character like a goblin without disadvantage, but that doesn't mean you can dual wield it but I think that one of these is enough. Even worse if they're a fighter they get to attack with their action, use their bonus action to attack again, attack twice using action surge, and use their reaction to attack again along with all the bonuses of this weapon. If they're a barbarian in a rage they get extra ac bonuses and a +2 to attack and damage rolls. If their a paladin they get to attack with their action, cast magic with their bonus action, and use their reaction to attack or cast magic during the enemies turn with all their bonuses using this weapon. If this is used as a finesse weapon you can dual wield it and  have 1d8 piercing damage or 1d6 slashing damage and use your dexterity modifier to add to your damage roll so rogues, sorcerers and bards have a high modifier to add  to their attacks. Sure it requires attunement but that just means you have to take a long rest to connect to it and focus all your power to it and use it's full power which is way too easy to do. So, yeah pretty broken. But you can have a lot of fun using this as a player.

Quote from LZiese >>

So in terms of role play... how does the player learn the command word? Trial and error? Magically via Attunement? After a long quest? Paying off a forge cleric or an artificer?  Love suggestions 

 RAW, you learn any and all command words for an item when you attune to it unless specified anyway.

could I get a flame tongue moon sickle.

91

I remember when i randomly gave one of my old pcs flametounge as a starting item...for some reason

Same here, it's the best

I figure this is a dumb question, but I'm curious on other people's opinions. I am currently playing a mute psionic (Kalashtar) soulknife rogue with telepathic abilities. What would be your rule in terms of magical items like this - would you allow your player, if their character is mute, to still activate this magical item? Or do you use their own flaw against them?

does this work under water?

yes it does

i have the weapon in my dnd beyond character sheet but how do i make it deal the extra 2d6 damage?

This wasn't my first magic item, but my favorite by far. It's a solid item. 

sus

Quote from Haydenm >>

How much gold would this sell for in a shop

It's valued in more than just gold, being not only a magic item, but a rare one. You could reasonably ask a buyer to sell their soul for it, if you so desired.

wow

Quote from Canadianguyog >>

This is a fun magic item to use as a player but a terrible item to give to a player as a DM, let me explain. Most people get this as a longsword which is good for players but a hell for DM's, imagine this your players are fighting an enemy and the fighter pulls out this, the problem is that since it's a versatile weapon they're now dealing five additional points of damage when they attack and get a +1 bonus to ac without a shield. Now they're dealing 2d6 fire damage, 1d8 slashing damage, 1d10 for regular damage, +5 to damage rolls, +2 to damage rolls as well (if proficient), versatile weapons allow you to use your strength modifier on your attack rolls, and since versatile weapons aren't heavy you can use this as a small character like a goblin without disadvantage, but that doesn't mean you can dual wield it but I think that one of these is enough. Even worse if they're a fighter they get to attack with their action, use their bonus action to attack again, attack twice using action surge, and use their reaction to attack again along with all the bonuses of this weapon. If they're a barbarian in a rage they get extra ac bonuses and a +2 to attack and damage rolls. If their a paladin they get to attack with their action, cast magic with their bonus action, and use their reaction to attack or cast magic during the enemies turn with all their bonuses using this weapon. If this is used as a finesse weapon you can dual wield it and  have 1d8 piercing damage or 1d6 slashing damage and use your dexterity modifier to add to your damage roll so rogues, sorcerers and bards have a high modifier to add  to their attacks. Sure it requires attunement but that just means you have to take a long rest to connect to it and focus all your power to it and use it's full power which is way too easy to do. So, yeah pretty broken. But you can have a lot of fun using this as a player.

 I have no idea how you came up with those numbers, they're not accurate at all.

First a fighter gets 1 attack at L1, 2 Atk at L5, 3 Atk at L11, and 4 Atk at L20 plus 1 action surge, 2 at L17.  A long sword cannot be used for two weapon fighting without a feat and is only 1d10 when wielded in two hands, so 1d8 OR 1d10 slashing + 2d6 fire + STR mod slashing. A bonus attack would only happen with TWF which would need either a short sword or the Duel wielder feat, attacks of opportunity are too rare to honesty be counted on in my opinion, unless you take sentinel another feat. 

I don't understand all these extra bonus actions and reactions you keep mentioning for other classes, unless you're using some kind of crazy homebrew, your descriptions of paladins and rogues is wrong, Barbs only get extra rage damage not at extra to hit. Sorcerers are not proficient with swords so they can't use it. Attunement takes a short rest not a long rest. Paladins either cast a spell or take the attack action unless they have a bonus action spell to use. Smites are not a bonus action they just happen. You can't use your reaction to cast a spell without Warcaster. I could go on and on but there's just too many errors in your post. Are you referring to an edition other than 5e? Cause none of that is 5e at all.

Also don't forget fire damage is the most commonly resisted or outright immune damage type enemies to have. The sword can be strong but it's not OP.

Is it possible to include 2d6 in the rolls? Or do I have to roll manually every time? If it's not possible is there a date for when this functionality will be added?

Can i control the command word?

Maybe it would take another short rest, if that would be how you get the command word in the first place.

I hate to ask but I am having a really difficult time finding similar weapons to this, does anyone have any idea if there are other weapons like flametongue with similar elemental effects that can also be a multitude of different weapon types?

If so where exactly can I find this info, yes I have a lot of the books but it is difficult to read all the way through 30 some books.