Test.ps1

function Test-Array {
    param (
        [string[]] $other = @(),
        [bool[]] $thisValue = @(),
        [bool[]] $Bold = @(),
        [bool[]] $Italic = @()
    )
    $thisValue.GetType()
    $bold.GetType()
    foreach ($value in $thisValue) {
        $value.GetType()
        $value
        #Test-Array -thisValue $value
    }
    for ($i = 0; $i -lt $thisValue.Count; $i++) {
        $thisValue[$i]
    }
}

function Set-WordText1 {
    [CmdletBinding()]
    param(
        [parameter(ValueFromPipelineByPropertyName, ValueFromPipeline)][Xceed.Words.NET.InsertBeforeOrAfter[]] $Paragraph,
        [alias ("C")] [System.Drawing.Color[]]$Color = @(),
        [alias ("S")] [double[]] $FontSize = @(),
        [alias ("FontName")] [string[]] $FontFamily = @(),
        [bool[]] $Bold = @(),
        [bool[]] $Italic = @(),
        [bool[]] $diff = @(),
        [alias ("U")] [UnderlineStyle[]] $UnderlineStyle = @(),
        [alias ('UC')] [System.Drawing.Color[]]$UnderlineColor = @(),
        [alias ("SA")] [double[]] $SpacingAfter = @(),
        [alias ("SB")] [double[]] $SpacingBefore = @(),
        [alias ("SP")] [double[]] $Spacing = @(),
        [alias ("H")] [highlight[]] $Highlight = @(),
        [alias ("CA")] [CapsStyle[]] $CapsStyle = @(),
        [alias ("ST")] [StrikeThrough[]] $StrikeThrough = @(),
        [alias ("HT")] [HeadingType[]] $HeadingType = @(),
        [int[]] $PercentageScale = @(), # "Value must be one of the following: 200, 150, 100, 90, 80, 66, 50 or 33"
        [Misc[]] $Misc = @(),
        [string[]] $Language = @(),
        [int[]]$Kerning = @(), # "Value must be one of the following: 8, 9, 10, 11, 12, 14, 16, 18, 20, 22, 24, 26, 28, 36, 48 or 72"
        [bool[]]$Hidden = @(),
        [int[]]$Position = @(), #  "Value must be in the range -1585 - 1585"
        [bool[]] $NewLine = @(),
        [switch] $KeepLinesTogether,
        [switch] $KeepWithNextParagraph,
        [single[]] $IndentationFirstLine = @(),
        [single[]] $IndentationHanging = @(),
        [Alignment[]] $Alignment = @(),
        [Direction[]] $Direction = @(),
        [ShadingType[]] $ShadingType = @(),
        [Script[]] $Script = @(),
        [bool] $Supress = $true
    )
    Write-Verbose "Set-WordText - Paragraph Count: $($Paragraph.Count)"
    Write-Verbose "Set-WordText - $($diff.GetType())"
    $bold.GetType()
    for ($i = 0; $i -lt $Paragraph.Count; $i++) {
        Write-Verbose "Set-WordText - Loop: $($i)"
        $Bold[$i].GetType()
        # $Paragraph[$i] = $Paragraph[$i] | Set-WordTextBold -Bold $Bold[$i] -Supress $false
        # $Paragraph[$i] = $Paragraph[$i] | Set-WordTextItalic -Italic $Italic[$i] -Supress $false

    }
}

Set-WordText1 -Paragraph $null, $null -Bold $null, $null -Verbose

Test-Array -thisValue $null, $null