Is it possible to use magic without saying "System Call" in Sword Art Online - Alicization?

Question

I was wondering if it's possible to execute system commands without saying 'System Call'. The anime series Sword Art Online: Alicization shows something like that but I was wondering if the characters really didn't say 'System Call' or it was just obviated and not shown to the spectators. In Chapter 21:

Kirito is fighting with Eugeo when he said: 'Burst Element' generating a powerful wind burst. But he didn't say 'System Call' nor 'Generate Aerial Element'.
Also, The Administrator healed the wounds of Eugeo without saying anything. In addition, she blocked Eugeo's attacks with a magical shield without saying any command.

I was wondering if both characters used the proper commands to cast magic but it wasn't shown to the spectators or in-universe, they didn't say anything.

Maybe they are so powerful that they no longer need to call the system using 'System Call', they just use telepathy or something like that due to their high authority level or a previous secret command? Or maybe the command was just skipped by the director of the anime?

Is there any clue about this on the manga or the novel? Anything? I love spoilers.

Answer 1

In the case of Quinella, she had previously used a ritual (which did involve evoking "System Call") which gave her body a permanent barrier to defend against all metal weapons. The Kirito and Eugeo fight probably was the anime skipping over the initial line, possibly with some excuse about "whispering" the line.

However, there is more to the "magic" in UnderWorld.

The Incarnating Arm that Eugeo used to retrieve his sword from Kirito is just one application to a very broad power. We've seen it portrayed in earlier episodes, but this world works on the power of imagination, Matrix-style, because of how all the Fluctlights in the Light Cube Cluster and Soul Translator are connected.
The incarnating arms are just one way to use this. Incarnation as its called can also reproduce the effects of System Calls, but this requires a particularly powerful imagination.

You'll see a lot more examples of this in the 3rd and 4th cours of Alicization (once that point is reached)